Add log level to show_stack()

Acked-by Steven Rostedt (VMware) <[email protected]>

---
 arch/microblaze/kernel/unwind.c | 2 +-
 arch/mips/kernel/traps.c        | 4 ++--
 arch/nds32/kernel/traps.c       | 4 ++--
 arch/riscv/kernel/stacktrace.c  | 2 +-
 include/linux/kallsyms.h        | 4 ++--
 kernel/locking/lockdep.c        | 4 ++--
 kernel/sched/core.c             | 6 ++----
 kernel/trace/ftrace.c           | 8 ++++----
 tools/include/linux/kallsyms.h  | 2 +-
 9 files changed, 17 insertions(+), 19 deletions(-)

arch/microblaze/kernel/unwind.c +1 -1

index 34c270cb11fc..4241cdd28ee7 100644
@@ -254,7 +254,7 @@ static void microblaze_unwind_inner(struct task_struct *task,
 					task->comm);
 				break;
 			} else
-				print_ip_sym(pc);
+				print_ip_sym(KERN_INFO, pc);
 		}
 
 		/* Stop when we reach anything not part of the kernel */

arch/mips/kernel/traps.c +2 -2

index 31968cbd6464..de05503c680c 100644
@@ -123,7 +123,7 @@ static void show_raw_backtrace(unsigned long reg29)
 			break;
 		}
 		if (__kernel_text_address(addr))
-			print_ip_sym(addr);
+			print_ip_sym(KERN_DEFAULT, addr);
 	}
 	printk("\n");
 }

@@ -153,7 +153,7 @@ static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
 	}
 	printk("Call Trace:\n");
 	do {
-		print_ip_sym(pc);
+		print_ip_sym(KERN_DEFAULT, pc);
 		pc = unwind_stack(task, &sp, pc, &ra);
 	} while (pc);
 	pr_cont("\n");

arch/nds32/kernel/traps.c +2 -2

index f4d386b52622..40625760a125 100644
@@ -108,7 +108,7 @@ static void __dump(struct task_struct *tsk, unsigned long *base_reg)
 			if (__kernel_text_address(ret_addr)) {
 				ret_addr = ftrace_graph_ret_addr(
 						tsk, &graph, ret_addr, NULL);
-				print_ip_sym(ret_addr);
+				print_ip_sym(KERN_EMERG, ret_addr);
 			}
 			if (--cnt < 0)
 				break;

@@ -124,7 +124,7 @@ static void __dump(struct task_struct *tsk, unsigned long *base_reg)
 
 				ret_addr = ftrace_graph_ret_addr(
 						tsk, &graph, ret_addr, NULL);
-				print_ip_sym(ret_addr);
+				print_ip_sym(KERN_EMERG, ret_addr);
 			}
 			if (--cnt < 0)
 				break;

arch/riscv/kernel/stacktrace.c +1 -1

index 0940681d2f68..a76892b48fff 100644
@@ -98,7 +98,7 @@ static void notrace walk_stackframe(struct task_struct *task,
 
 static bool print_trace_address(unsigned long pc, void *arg)
 {
-	print_ip_sym(pc);
+	print_ip_sym(KERN_DEFAULT, pc);
 	return false;
 }

include/linux/kallsyms.h +2 -2

index 657a83b943f0..98338dc6b5d2 100644
@@ -165,9 +165,9 @@ static inline int kallsyms_show_value(void)
 
 #endif /*CONFIG_KALLSYMS*/
 
-static inline void print_ip_sym(unsigned long ip)
+static inline void print_ip_sym(const char *loglvl, unsigned long ip)
 {
-	printk("[<%px>] %pS\n", (void *) ip, (void *) ip);
+	printk("%s[<%px>] %pS\n", loglvl, (void *) ip, (void *) ip);
 }
 
 #endif /*_LINUX_KALLSYMS_H*/

kernel/locking/lockdep.c +2 -2

index 32406ef0d6a2..af819bb6874b 100644
@@ -3998,7 +3998,7 @@ static void print_unlock_imbalance_bug(struct task_struct *curr,
 		curr->comm, task_pid_nr(curr));
 	print_lockdep_cache(lock);
 	pr_cont(") at:\n");
-	print_ip_sym(ip);
+	print_ip_sym(KERN_WARNING, ip);
 	pr_warn("but there are no more locks to release!\n");
 	pr_warn("\nother info that might help us debug this:\n");
 	lockdep_print_held_locks(curr);

@@ -4600,7 +4600,7 @@ static void print_lock_contention_bug(struct task_struct *curr,
 		curr->comm, task_pid_nr(curr));
 	print_lockdep_cache(lock);
 	pr_cont(") at:\n");
-	print_ip_sym(ip);
+	print_ip_sym(KERN_WARNING, ip);
 	pr_warn("but there are no locks held!\n");
 	pr_warn("\nother info that might help us debug this:\n");
 	lockdep_print_held_locks(curr);

kernel/sched/core.c +2 -4

index 1a9983da4408..2284deb3a83b 100644
@@ -3858,8 +3858,7 @@ static noinline void __schedule_bug(struct task_struct *prev)
 	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
 	    && in_atomic_preempt_off()) {
 		pr_err("Preemption disabled at:");
-		print_ip_sym(preempt_disable_ip);
-		pr_cont("\n");
+		print_ip_sym(KERN_ERR, preempt_disable_ip);
 	}
 	if (panic_on_warn)
 		panic("scheduling while atomic\n");

@@ -6792,8 +6791,7 @@ void ___might_sleep(const char *file, int line, int preempt_offset)
 	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
 	    && !preempt_count_equals(preempt_offset)) {
 		pr_err("Preemption disabled at:");
-		print_ip_sym(preempt_disable_ip);
-		pr_cont("\n");
+		print_ip_sym(KERN_ERR, preempt_disable_ip);
 	}
 	dump_stack();
 	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);

kernel/trace/ftrace.c +4 -4

index fd81c7de77a7..c377e290ba54 100644
@@ -2021,12 +2021,12 @@ void ftrace_bug(int failed, struct dyn_ftrace *rec)
 	case -EFAULT:
 		FTRACE_WARN_ON_ONCE(1);
 		pr_info("ftrace faulted on modifying ");
-		print_ip_sym(ip);
+		print_ip_sym(KERN_INFO, ip);
 		break;
 	case -EINVAL:
 		FTRACE_WARN_ON_ONCE(1);
 		pr_info("ftrace failed to modify ");
-		print_ip_sym(ip);
+		print_ip_sym(KERN_INFO, ip);
 		print_ip_ins(" actual:   ", (unsigned char *)ip);
 		pr_cont("\n");
 		if (ftrace_expected) {

@@ -2037,12 +2037,12 @@ void ftrace_bug(int failed, struct dyn_ftrace *rec)
 	case -EPERM:
 		FTRACE_WARN_ON_ONCE(1);
 		pr_info("ftrace faulted on writing ");
-		print_ip_sym(ip);
+		print_ip_sym(KERN_INFO, ip);
 		break;
 	default:
 		FTRACE_WARN_ON_ONCE(1);
 		pr_info("ftrace faulted on unknown error ");
-		print_ip_sym(ip);
+		print_ip_sym(KERN_INFO, ip);
 	}
 	print_bug_type();
 	if (rec) {

tools/include/linux/kallsyms.h +1 -1

index 89ca6fe257cc..efb6c3f5f2a9 100644
@@ -20,7 +20,7 @@ static inline const char *kallsyms_lookup(unsigned long addr,
 
 #include <execinfo.h>
 #include <stdlib.h>
-static inline void print_ip_sym(unsigned long ip)
+static inline void print_ip_sym(const char *loglvl, unsigned long ip)
 {
 	char **name;

Signature · 1 line

2.25.1

Joe Perches

2020-03-16 15:31 UTC #2 lore raw

Re: [PATCHv2 01/50] kallsyms/printk: Add loglvl to print_ip_sym()

Quoted 3 lines · Dmitry Safonov

print_ip_sym() needs to have a log level parameter to comply with other parts being printed. Otherwise, half of the expected backtrace would be printed and other may be missing with some logging level.

There are 15 instances of print_ip_sym.

Perhaps it'd be better to get rid of print_ip_sym
altogether by expanding it in-place instead.

Quoted 9 lines

 arch/microblaze/kernel/unwind.c | 2 +-
 arch/mips/kernel/traps.c        | 4 ++--
 arch/nds32/kernel/traps.c       | 4 ++--
 arch/riscv/kernel/stacktrace.c  | 2 +-
 include/linux/kallsyms.h        | 4 ++--
 kernel/locking/lockdep.c        | 4 ++--
 kernel/sched/core.c             | 6 ++----
 kernel/trace/ftrace.c           | 8 ++++----
 tools/include/linux/kallsyms.h  | 2 +-

Dmitry Safonov

author

2020-04-17 22:59 UTC #3 lore raw

Re: [PATCHv2 01/50] kallsyms/printk: Add loglvl to print_ip_sym()

Hi Joe,

Quoted 9 lines · Joe Perches

Quoted 3 lines · Dmitry Safonov
print_ip_sym() needs to have a log level parameter to comply with other parts being printed. Otherwise, half of the expected backtrace would be printed and other may be missing with some logging level.
There are 15 instances of print_ip_sym.
Perhaps it'd be better to get rid of print_ip_sym
altogether by expanding it in-place instead.

I tried this and format-string + two casts to (void *) take some space and the resulting printk() doesn't fit 80 cols.
I guess, it's minor and it can be done on the top of v3..

Quoted 12 lines

Quoted 10 lines

 arch/microblaze/kernel/unwind.c | 2 +-
 arch/mips/kernel/traps.c        | 4 ++--
 arch/nds32/kernel/traps.c       | 4 ++--
 arch/riscv/kernel/stacktrace.c  | 2 +-
 include/linux/kallsyms.h        | 4 ++--
 kernel/locking/lockdep.c        | 4 ++--
 kernel/sched/core.c             | 6 ++----
 kernel/trace/ftrace.c           | 8 ++++----
 tools/include/linux/kallsyms.h  | 2 +-

Thanks,
Dmitry

Dmitry Safonov

author

2020-03-16 14:38 UTC #4 lore raw

PATCH v2 2/50 alpha: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Ivan Kokshaysky <[email protected]>
Cc: Matt Turner <[email protected]>
Cc: Richard Henderson <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/alpha/kernel/traps.c | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

arch/alpha/kernel/traps.c +17 ~~-11~~

index f6b9664ac504..2402f1777f54 100644
@@ -121,10 +121,10 @@ dik_show_code(unsigned int *pc)
 }
 
 static void
-dik_show_trace(unsigned long *sp)
+dik_show_trace(unsigned long *sp, const char *loglvl)
 {
 	long i = 0;
-	printk("Trace:\n");
+	printk("%sTrace:\n", loglvl);
 	while (0x1ff8 & (unsigned long) sp) {
 		extern char _stext[], _etext[];
 		unsigned long tmp = *sp;

@@ -133,24 +133,25 @@ dik_show_trace(unsigned long *sp)
 			continue;
 		if (tmp >= (unsigned long) &_etext)
 			continue;
-		printk("[<%lx>] %pSR\n", tmp, (void *)tmp);
+		printk("%s[<%lx>] %pSR\n", loglvl, tmp, (void *)tmp);
 		if (i > 40) {
-			printk(" ...");
+			printk("%s ...", loglvl);
 			break;
 		}
 	}
-	printk("\n");
+	printk("%s\n", loglvl);
 }
 
 static int kstack_depth_to_print = 24;
 
-void show_stack(struct task_struct *task, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+			const char *loglvl)
 {
 	unsigned long *stack;
 	int i;
 
 	/*
-	 * debugging aid: "show_stack(NULL);" prints the
+	 * debugging aid: "show_stack(NULL, NULL, KERN_EMERG);" prints the
 	 * back trace for this cpu.
 	 */
 	if(sp==NULL)

@@ -163,14 +164,19 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 		if ((i % 4) == 0) {
 			if (i)
 				pr_cont("\n");
-			printk("       ");
+			printk("%s       ", loglvl);
 		} else {
 			pr_cont(" ");
 		}
 		pr_cont("%016lx", *stack++);
 	}
 	pr_cont("\n");
-	dik_show_trace(sp);
+	dik_show_trace(sp, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT);
 }
 
 void

@@ -184,7 +190,7 @@ die_if_kernel(char * str, struct pt_regs *regs, long err, unsigned long *r9_15)
 	printk("%s(%d): %s %ld\n", current->comm, task_pid_nr(current), str, err);
 	dik_show_regs(regs, r9_15);
 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
-	dik_show_trace((unsigned long *)(regs+1));
+	dik_show_trace((unsigned long *)(regs+1), KERN_DEFAULT);
 	dik_show_code((unsigned int *)regs->pc);
 
 	if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) {

@@ -625,7 +631,7 @@ do_entUna(void * va, unsigned long opcode, unsigned long reg,
 	printk("gp = %016lx  sp = %p\n", regs->gp, regs+1);
 
 	dik_show_code((unsigned int *)pc);
-	dik_show_trace((unsigned long *)(regs+1));
+	dik_show_trace((unsigned long *)(regs+1), KERN_DEFAULT);
 
 	if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) {
 		printk("die_if_kernel recursion detected.\n");

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:39 UTC #5 lore raw

PATCH v2 3/50 arc: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

As a good side-effect header "Stack Trace:" is now printed with the same log level as the rest of backtrace.

Cc: Vineet Gupta <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/arc/include/asm/bug.h     |  3 ++-
 arch/arc/kernel/stacktrace.c   | 21 +++++++++++++++------
 arch/arc/kernel/troubleshoot.c |  2 +-
 3 files changed, 18 insertions(+), 8 deletions(-)

arch/arc/include/asm/bug.h +2 -1

index 0be19fd1a412..4c453ba96c51 100644
@@ -13,7 +13,8 @@
 struct task_struct;
 
 void show_regs(struct pt_regs *regs);
-void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs);
+void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs,
+		     const char *loglvl);
 void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
 			    unsigned long address);
 void die(const char *str, struct pt_regs *regs, unsigned long address);

arch/arc/kernel/stacktrace.c +15 -6

index 1e440bbfa876..24f9cd8a12c9 100644
@@ -158,9 +158,11 @@ arc_unwind_core(struct task_struct *tsk, struct pt_regs *regs,
 /* Call-back which plugs into unwinding core to dump the stack in
  * case of panic/OOPs/BUG etc
  */
-static int __print_sym(unsigned int address, void *unused)
+static int __print_sym(unsigned int address, void *arg)
 {
-	printk("  %pS\n", (void *)address);
+	const char *loglvl = arg;
+
+	printk("%s  %pS\n", loglvl, (void *)address);
 	return 0;
 }

@@ -217,17 +219,24 @@ static int __get_first_nonsched(unsigned int address, void *unused)
  *-------------------------------------------------------------------------
  */
 
-noinline void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs)
+noinline void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs,
+			      const char *loglvl)
 {
-	pr_info("\nStack Trace:\n");
-	arc_unwind_core(tsk, regs, __print_sym, NULL);
+	printk("%s\nStack Trace:\n", loglvl);
+	arc_unwind_core(tsk, regs, __print_sym, (void *)loglvl);
 }
 EXPORT_SYMBOL(show_stacktrace);
 
 /* Expected by sched Code */
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
+			const char *loglvl)
+{
+	show_stacktrace(tsk, NULL, loglvl);
+}
+
 void show_stack(struct task_struct *tsk, unsigned long *sp)
 {
-	show_stacktrace(tsk, NULL);
+	show_stack_loglvl(tsk, sp, KERN_DEFAULT);
 }
 
 /* Another API expected by schedular, shows up in "ps" as Wait Channel

arch/arc/kernel/troubleshoot.c +1 -1

index d2999503fb8a..660681101523 100644
@@ -242,5 +242,5 @@ void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
 
 	/* Show stack trace if this Fatality happened in kernel mode */
 	if (!user_mode(regs))
-		show_stacktrace(current, regs);
+		show_stacktrace(current, regs, KERN_DEFAULT);
 }

Signature · 7 lines

2.25.1


_______________________________________________
linux-snps-arc mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

Dmitry Safonov

author

2020-03-16 14:40 UTC #6 lore raw

PATCH v2 4/50 arm/asm: Add loglvl to c_backtrace()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Add log level argument to c_backtrace() as a preparation for introducing show_stack_loglvl().

Cc: Russell King <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/arm/include/asm/bug.h     |  3 ++-
 arch/arm/include/asm/traps.h   |  3 ++-
 arch/arm/kernel/traps.c        |  9 +++++----
 arch/arm/kernel/unwind.c       |  2 +-
 arch/arm/lib/backtrace-clang.S |  9 +++++++--
 arch/arm/lib/backtrace.S       | 14 ++++++++++----
 6 files changed, 27 insertions(+), 13 deletions(-)

arch/arm/include/asm/bug.h +2 -1

index deef4d0cb3b5..673c7dd75ab9 100644
@@ -82,7 +82,8 @@ void hook_ifault_code(int nr, int (*fn)(unsigned long, unsigned int,
 				       struct pt_regs *),
 		     int sig, int code, const char *name);
 
-extern asmlinkage void c_backtrace(unsigned long fp, int pmode);
+extern asmlinkage void c_backtrace(unsigned long fp, int pmode,
+				   const char *loglvl);
 
 struct mm_struct;
 void show_pte(const char *lvl, struct mm_struct *mm, unsigned long addr);

arch/arm/include/asm/traps.h +2 -1

index 172b08ff3760..987fefb0a4db 100644
@@ -29,7 +29,8 @@ static inline int __in_irqentry_text(unsigned long ptr)
 }
 
 extern void __init early_trap_init(void *);
-extern void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame);
+extern void dump_backtrace_entry(unsigned long where, unsigned long from,
+				 unsigned long frame, const char *loglvl);
 extern void ptrace_break(struct pt_regs *regs);
 
 extern void *vectors_page;

arch/arm/kernel/traps.c +5 -4

index 1e70e7227f0f..2030611f22b8 100644
@@ -62,7 +62,8 @@ __setup("user_debug=", user_debug_setup);
 
 static void dump_mem(const char *, const char *, unsigned long, unsigned long);
 
-void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
+void dump_backtrace_entry(unsigned long where, unsigned long from,
+			  unsigned long frame, const char *loglvl)
 {
 	unsigned long end = frame + 4 + sizeof(struct pt_regs);

@@ -76,7 +77,7 @@ void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long
 		dump_mem("", "Exception stack", frame + 4, end);
 }
 
-void dump_backtrace_stm(u32 *stack, u32 instruction)
+void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl)
 {
 	char str[80], *p;
 	unsigned int x;

@@ -238,7 +239,7 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 	pr_cont("\n");
 
 	if (ok)
-		c_backtrace(fp, mode);
+		c_backtrace(fp, mode, NULL);
 }
 #endif

@@ -666,7 +667,7 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
 		dump_instr("", regs);
 		if (user_mode(regs)) {
 			__show_regs(regs);
-			c_backtrace(frame_pointer(regs), processor_mode(regs));
+			c_backtrace(frame_pointer(regs), processor_mode(regs), NULL);
 		}
 	}
 #endif

arch/arm/kernel/unwind.c +1 -1

index 4574e6aea0a5..0a65005e10f0 100644
@@ -493,7 +493,7 @@ void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 		urc = unwind_frame(&frame);
 		if (urc < 0)
 			break;
-		dump_backtrace_entry(where, frame.pc, frame.sp - 4);
+		dump_backtrace_entry(where, frame.pc, frame.sp - 4, NULL);
 	}
 }

arch/arm/lib/backtrace-clang.S +7 -2

index 2ff375144b55..6174c45f53a5 100644
@@ -17,6 +17,7 @@
 #define sv_pc	r6
 #define mask	r7
 #define sv_lr	r8
+#define loglvl	r9
 
 ENTRY(c_backtrace)

@@ -99,6 +100,7 @@ ENDPROC(c_backtrace)
 						@ to ensure 8 byte alignment
 		movs	frame, r0		@ if frame pointer is zero
 		beq	no_frame		@ we have no stack frames
+		mov	loglvl, r2
 		tst	r1, #0x10		@ 26 or 32-bit mode?
 		moveq	mask, #0xfc000003
 		movne	mask, #0		@ mask for 32-bit

@@ -167,6 +169,7 @@ finished_setup:
 		mov	r1, sv_lr
 		mov	r2, frame
 		bic	r1, r1, mask		@ mask PC/LR for the mode
+		mov	r3, loglvl
 		bl	dump_backtrace_entry
 
 /*

@@ -183,6 +186,7 @@ finished_setup:
 		ldr	r0, [frame]		@ locals are stored in
 						@ the preceding frame
 		subeq	r0, r0, #4
+		mov	r2, loglvl
 		bleq	dump_backtrace_stm	@ dump saved registers
 
 /*

@@ -196,7 +200,8 @@ finished_setup:
 		bhi	for_each_frame
 
 1006:		adr	r0, .Lbad
-		mov	r1, frame
+		mov	r1, loglvl
+		mov	r2, frame
 		bl	printk
 no_frame:	ldmfd	sp!, {r4 - r9, fp, pc}
 ENDPROC(c_backtrace)

@@ -209,7 +214,7 @@ ENDPROC(c_backtrace)
 		.long   1005b, 1006b
 		.popsection
 
-.Lbad:		.asciz	"Backtrace aborted due to bad frame pointer <%p>\n"
+.Lbad:		.asciz	"%sBacktrace aborted due to bad frame pointer <%p>\n"
 		.align
 .Lopcode:	.word	0xe92d4800 >> 11	@ stmfd sp!, {... fp, lr}
 		.word	0x0b000000		@ bl if these bits are set

arch/arm/lib/backtrace.S +10 -4

index 582925238d65..872f658638d9 100644
@@ -18,6 +18,7 @@
 #define sv_pc	r6
 #define mask	r7
 #define offset	r8
+#define loglvl	r9
 
 ENTRY(c_backtrace)

@@ -25,9 +26,10 @@ ENTRY(c_backtrace)
 		ret	lr
 ENDPROC(c_backtrace)
 #else
-		stmfd	sp!, {r4 - r8, lr}	@ Save an extra register so we have a location...
+		stmfd	sp!, {r4 - r9, lr}	@ Save an extra register so we have a location...
 		movs	frame, r0		@ if frame pointer is zero
 		beq	no_frame		@ we have no stack frames
+		mov	loglvl, r2
 
 		tst	r1, #0x10		@ 26 or 32-bit mode?
  ARM(		moveq	mask, #0xfc000003	)

@@ -73,6 +75,7 @@ for_each_frame:	tst	frame, mask		@ Check for address exceptions
 		ldr	r1, [frame, #-4]	@ get saved lr
 		mov	r2, frame
 		bic	r1, r1, mask		@ mask PC/LR for the mode
+		mov	r3, loglvl
 		bl	dump_backtrace_entry
 
 		ldr	r1, [sv_pc, #-4]	@ if stmfd sp!, {args} exists,

@@ -80,12 +83,14 @@ for_each_frame:	tst	frame, mask		@ Check for address exceptions
 		teq	r3, r1, lsr #11
 		ldreq	r0, [frame, #-8]	@ get sp
 		subeq	r0, r0, #4		@ point at the last arg
+		mov	r2, loglvl
 		bleq	dump_backtrace_stm	@ dump saved registers
 
 1004:		ldr	r1, [sv_pc, #0]		@ if stmfd sp!, {..., fp, ip, lr, pc}
 		ldr	r3, .Ldsi		@ instruction exists,
 		teq	r3, r1, lsr #11
 		subeq	r0, frame, #16
+		mov	r2, loglvl
 		bleq	dump_backtrace_stm	@ dump saved registers
 
 		teq	sv_fp, #0		@ zero saved fp means

@@ -96,9 +101,10 @@ for_each_frame:	tst	frame, mask		@ Check for address exceptions
 		bhi	for_each_frame
 
 1006:		adr	r0, .Lbad
-		mov	r1, frame
+		mov	r1, loglvl
+		mov	r2, frame
 		bl	printk
-no_frame:	ldmfd	sp!, {r4 - r8, pc}
+no_frame:	ldmfd	sp!, {r4 - r9, pc}
 ENDPROC(c_backtrace)
 		
 		.pushsection __ex_table,"a"

@@ -109,7 +115,7 @@ ENDPROC(c_backtrace)
 		.long	1004b, 1006b
 		.popsection
 
-.Lbad:		.asciz	"Backtrace aborted due to bad frame pointer <%p>\n"
+.Lbad:		.asciz	"%sBacktrace aborted due to bad frame pointer <%p>\n"
 		.align
 .Ldsi:		.word	0xe92dd800 >> 11	@ stmfd sp!, {... fp, ip, lr, pc}
 		.word	0xe92d0000 >> 11	@ stmfd sp!, {}

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:40 UTC #7 lore raw

PATCH v2 5/50 arm: Add loglvl to unwind_backtrace()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Add log level argument to unwind_backtrace() as a preparation for introducing show_stack_loglvl().

As a good side-effect arm_syscall() is now printing errors with the same log level as the backtrace.

Cc: Russell King <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/arm/include/asm/unwind.h | 3 ++-
 arch/arm/kernel/traps.c       | 6 +++---
 arch/arm/kernel/unwind.c      | 5 +++--
 3 files changed, 8 insertions(+), 6 deletions(-)

arch/arm/include/asm/unwind.h +2 -1

index 6e282c33126b..0f8a3439902d 100644
@@ -36,7 +36,8 @@ extern struct unwind_table *unwind_table_add(unsigned long start,
 					     unsigned long text_addr,
 					     unsigned long text_size);
 extern void unwind_table_del(struct unwind_table *tab);
-extern void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk);
+extern void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+			     const char *loglvl);
 
 #endif	/* !__ASSEMBLY__ */

arch/arm/kernel/traps.c +3 -3

index 2030611f22b8..685e17c2e275 100644
@@ -204,7 +204,7 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
 #ifdef CONFIG_ARM_UNWIND
 static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 {
-	unwind_backtrace(regs, tsk);
+	unwind_backtrace(regs, tsk, KERN_DEFAULT);
 }
 #else
 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)

@@ -664,10 +664,10 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
 	if (user_debug & UDBG_SYSCALL) {
 		pr_err("[%d] %s: arm syscall %d\n",
 		       task_pid_nr(current), current->comm, no);
-		dump_instr("", regs);
+		dump_instr(KERN_ERR, regs);
 		if (user_mode(regs)) {
 			__show_regs(regs);
-			c_backtrace(frame_pointer(regs), processor_mode(regs), NULL);
+			c_backtrace(frame_pointer(regs), processor_mode(regs), KERN_ERR);
 		}
 	}
 #endif

arch/arm/kernel/unwind.c +3 -2

index 0a65005e10f0..9222649ebe0f 100644
@@ -455,7 +455,8 @@ int unwind_frame(struct stackframe *frame)
 	return URC_OK;
 }
 
-void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk)
+void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+		      const char *loglvl)
 {
 	struct stackframe frame;

@@ -493,7 +494,7 @@ void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 		urc = unwind_frame(&frame);
 		if (urc < 0)
 			break;
-		dump_backtrace_entry(where, frame.pc, frame.sp - 4, NULL);
+		dump_backtrace_entry(where, frame.pc, frame.sp - 4, loglvl);
 	}
 }

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:40 UTC #8 lore raw

PATCH v2 6/50 arm: Add loglvl to dump_backtrace()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Add log level argument to dump_backtrace() as a preparation for introducing show_stack_loglvl().

As a good side-effect __die() now prints not only "Stack:" header with KERN_EMERG, but the backtrace itself.

Cc: Russell King <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/arm/kernel/traps.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

arch/arm/kernel/traps.c +9 -7

index 685e17c2e275..0f09ace18e6c 100644
@@ -202,17 +202,19 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
 }
 
 #ifdef CONFIG_ARM_UNWIND
-static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
+static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+				  const char *loglvl)
 {
-	unwind_backtrace(regs, tsk, KERN_DEFAULT);
+	unwind_backtrace(regs, tsk, loglvl);
 }
 #else
-static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
+static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+			   const char *loglvl)
 {
 	unsigned int fp, mode;
 	int ok = 1;
 
-	printk("Backtrace: ");
+	printk("%sBacktrace: ", loglvl);
 
 	if (!tsk)
 		tsk = current;

@@ -239,13 +241,13 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 	pr_cont("\n");
 
 	if (ok)
-		c_backtrace(fp, mode, NULL);
+		c_backtrace(fp, mode, loglvl);
 }
 #endif
 
 void show_stack(struct task_struct *tsk, unsigned long *sp)
 {
-	dump_backtrace(NULL, tsk);
+	dump_backtrace(NULL, tsk, KERN_DEFAULT);
 	barrier();
 }

@@ -289,7 +291,7 @@ static int __die(const char *str, int err, struct pt_regs *regs)
 	if (!user_mode(regs) || in_interrupt()) {
 		dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
 			 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
-		dump_backtrace(regs, tsk);
+		dump_backtrace(regs, tsk, KERN_EMERG);
 		dump_instr(KERN_EMERG, regs);
 	}

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:40 UTC #9 lore raw

PATCH v2 7/50 arm: Wire up dump_backtrace_{entry,stm}

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Now that c_backtrace() always emits correct loglvl, use it for printing.

Cc: Russell King <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/arm/kernel/traps.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

arch/arm/kernel/traps.c +7 -5

index 0f09ace18e6c..e1be6c85327c 100644
@@ -68,13 +68,15 @@ void dump_backtrace_entry(unsigned long where, unsigned long from,
 	unsigned long end = frame + 4 + sizeof(struct pt_regs);
 
 #ifdef CONFIG_KALLSYMS
-	printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
+	printk("%s[<%08lx>] (%ps) from [<%08lx>] (%pS)\n",
+		loglvl, where, (void *)where, from, (void *)from);
 #else
-	printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
+	printk("%sFunction entered at [<%08lx>] from [<%08lx>]\n",
+		loglvl, where, from);
 #endif
 
 	if (in_entry_text(from) && end <= ALIGN(frame, THREAD_SIZE))
-		dump_mem("", "Exception stack", frame + 4, end);
+		dump_mem(loglvl, "Exception stack", frame + 4, end);
 }
 
 void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl)

@@ -89,12 +91,12 @@ void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl)
 			if (++x == 6) {
 				x = 0;
 				p = str;
-				printk("%s\n", str);
+				printk("%s%s\n", loglvl, str);
 			}
 		}
 	}
 	if (p != str)
-		printk("%s\n", str);
+		printk("%s%s\n", loglvl, str);
 }
 
 #ifndef CONFIG_ARM_UNWIND

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:40 UTC #10 lore raw

PATCH v2 8/50 arm: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Russell King <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/arm/kernel/traps.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

arch/arm/kernel/traps.c +8 -2

index e1be6c85327c..00455b5bbf8a 100644
@@ -247,12 +247,18 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
 }
 #endif
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
+		       const char *loglvl)
 {
-	dump_backtrace(NULL, tsk, KERN_DEFAULT);
+	dump_backtrace(NULL, tsk, loglvl);
 	barrier();
 }
 
+void show_stack(struct task_struct *tsk, unsigned long *sp)
+{
+	show_stack_loglvl(tsk, sp, KERN_DEFAULT);
+}
+
 #ifdef CONFIG_PREEMPT
 #define S_PREEMPT " PREEMPT"
 #elif defined(CONFIG_PREEMPT_RT)

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:40 UTC #11 lore raw

PATCH v2 9/50 arm64: Add loglvl to dump_backtrace()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Add log level argument to dump_backtrace() as a preparation for introducing show_stack_loglvl().

Cc: Catalin Marinas <[email protected]>
Cc: Russell King <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/arm64/include/asm/stacktrace.h |  3 ++-
 arch/arm64/kernel/process.c         |  2 +-
 arch/arm64/kernel/traps.c           | 15 ++++++++-------
 3 files changed, 11 insertions(+), 9 deletions(-)

arch/arm64/include/asm/stacktrace.h +2 -1

index 4d9b1f48dc39..fdb913cc0bcb 100644
@@ -64,7 +64,8 @@ struct stackframe {
 extern int unwind_frame(struct task_struct *tsk, struct stackframe *frame);
 extern void walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
 			    int (*fn)(struct stackframe *, void *), void *data);
-extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk);
+extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+			   const char *loglvl);
 
 DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);

arch/arm64/kernel/process.c +1 -1

index 00626057a384..2ee44d95f023 100644
@@ -291,7 +291,7 @@ void __show_regs(struct pt_regs *regs)
 void show_regs(struct pt_regs * regs)
 {
 	__show_regs(regs);
-	dump_backtrace(regs, NULL);
+	dump_backtrace(regs, NULL, KERN_DEFAULT);
 }
 
 static void tls_thread_flush(void)

arch/arm64/kernel/traps.c +8 -7

index cf402be5c573..6e777cbd4eb5 100644
@@ -53,9 +53,9 @@ static const char *handler[]= {
 
 int show_unhandled_signals = 0;
 
-static void dump_backtrace_entry(unsigned long where)
+static void dump_backtrace_entry(unsigned long where, const char *loglvl)
 {
-	printk(" %pS\n", (void *)where);
+	printk("%s %pS\n", loglvl, (void *)where);
 }
 
 static void dump_kernel_instr(const char *lvl, struct pt_regs *regs)

@@ -83,7 +83,8 @@ static void dump_kernel_instr(const char *lvl, struct pt_regs *regs)
 	printk("%sCode: %s\n", lvl, str);
 }
 
-void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
+void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+		    const char *loglvl)
 {
 	struct stackframe frame;
 	int skip = 0;

@@ -115,11 +116,11 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 				thread_saved_pc(tsk));
 	}
 
-	printk("Call trace:\n");
+	printk("%sCall trace:\n", loglvl);
 	do {
 		/* skip until specified stack frame */
 		if (!skip) {
-			dump_backtrace_entry(frame.pc);
+			dump_backtrace_entry(frame.pc, loglvl);
 		} else if (frame.fp == regs->regs[29]) {
 			skip = 0;
 			/*

@@ -129,7 +130,7 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 			 * at which an exception has taken place, use regs->pc
 			 * instead.
 			 */
-			dump_backtrace_entry(regs->pc);
+			dump_backtrace_entry(regs->pc, loglvl);
 		}
 	} while (!unwind_frame(tsk, &frame));

@@ -138,7 +139,7 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 
 void show_stack(struct task_struct *tsk, unsigned long *sp)
 {
-	dump_backtrace(NULL, tsk);
+	dump_backtrace(NULL, tsk, KERN_DEFAULT);
 	barrier();
 }

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:40 UTC #12 lore raw

PATCH v2 10/50 arm64: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Catalin Marinas <[email protected]>
Cc: Russell King <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/arm64/kernel/traps.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

arch/arm64/kernel/traps.c +8 -2

index 6e777cbd4eb5..516e92332fd0 100644
@@ -137,12 +137,18 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
 	put_task_stack(tsk);
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
+		       const char *loglvl)
 {
-	dump_backtrace(NULL, tsk, KERN_DEFAULT);
+	dump_backtrace(NULL, tsk, loglvl);
 	barrier();
 }
 
+void show_stack(struct task_struct *tsk, unsigned long *sp)
+{
+	show_stack_loglvl(tsk, sp, KERN_DEFAULT);
+}
+
 #ifdef CONFIG_PREEMPT
 #define S_PREEMPT " PREEMPT"
 #elif defined(CONFIG_PREEMPT_RT)

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:40 UTC #13 lore raw

PATCH v2 11/50 c6x: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Aurelien Jacquiot <[email protected]>
Cc: Mark Salter <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/c6x/kernel/traps.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

arch/c6x/kernel/traps.c +14 -7

index ec61034fdf56..4afbf48f1ce0 100644
@@ -344,12 +344,13 @@ asmlinkage int process_exception(struct pt_regs *regs)
 
 static int kstack_depth_to_print = 48;
 
-static void show_trace(unsigned long *stack, unsigned long *endstack)
+static void show_trace(unsigned long *stack, unsigned long *endstack,
+		       const char *loglvl)
 {
 	unsigned long addr;
 	int i;
 
-	pr_debug("Call trace:");
+	printk("%sCall trace:", loglvl);
 	i = 0;
 	while (stack + 1 <= endstack) {
 		addr = *stack++;

@@ -364,16 +365,17 @@ static void show_trace(unsigned long *stack, unsigned long *endstack)
 		if (__kernel_text_address(addr)) {
 #ifndef CONFIG_KALLSYMS
 			if (i % 5 == 0)
-				pr_debug("\n	    ");
+				printk("%s\n	    ", loglvl);
 #endif
-			pr_debug(" [<%08lx>] %pS\n", addr, (void *)addr);
+			printk("%s [<%08lx>] %pS\n", loglvl, addr, (void *)addr);
 			i++;
 		}
 	}
-	pr_debug("\n");
+	printk("%s\n", loglvl);
 }
 
-void show_stack(struct task_struct *task, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+		const char *loglvl)
 {
 	unsigned long *p, *endstack;
 	int i;

@@ -398,7 +400,12 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 		pr_cont(" %08lx", *p++);
 	}
 	pr_cont("\n");
-	show_trace(stack, endstack);
+	show_trace(stack, endstack, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *stack)
+{
+	show_stack_loglvl(task, stack, KERN_DEBUG);
 }
 
 int is_valid_bugaddr(unsigned long addr)

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:40 UTC #14 lore raw

PATCH v2 12/50 csky: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Guo Ren <[email protected]>
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/csky/kernel/dumpstack.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

arch/csky/kernel/dumpstack.c +10 -4

index d67f9777cfd9..c500837390d3 100644
@@ -5,7 +5,7 @@
 
 int kstack_depth_to_print = 48;
 
-void show_trace(unsigned long *stack)
+static void show_trace(unsigned long *stack, const char *loglvl)
 {
 	unsigned long *stack_end;
 	unsigned long *stack_start;

@@ -17,7 +17,7 @@ void show_trace(unsigned long *stack)
 	stack_end = (unsigned long *) (addr + THREAD_SIZE);
 
 	fp = stack;
-	pr_info("\nCall Trace:");
+	printk("%s\nCall Trace:", loglvl);
 
 	while (fp > stack_start && fp < stack_end) {
 #ifdef CONFIG_STACKTRACE

@@ -32,7 +32,8 @@ void show_trace(unsigned long *stack)
 	pr_cont("\n");
 }
 
-void show_stack(struct task_struct *task, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+		const char *loglvl)
 {
 	if (!stack) {
 		if (task)

@@ -45,5 +46,10 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 #endif
 	}
 
-	show_trace(stack);
+	show_trace(stack, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *stack)
+{
+	show_stack_loglvl(task, stack, KERN_INFO);
 }

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:40 UTC #15 lore raw

PATCH v2 13/50 h8300: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Yoshinori Sato <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/h8300/kernel/traps.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

arch/h8300/kernel/traps.c +12 -6

index e47a9e0dc278..6362446563d6 100644
@@ -115,7 +115,8 @@ void die(const char *str, struct pt_regs *fp, unsigned long err)
 
 static int kstack_depth_to_print = 24;
 
-void show_stack(struct task_struct *task, unsigned long *esp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *esp,
+		       const char *loglvl)
 {
 	unsigned long *stack,  addr;
 	int i;

@@ -125,17 +126,17 @@ void show_stack(struct task_struct *task, unsigned long *esp)
 
 	stack = esp;
 
-	pr_info("Stack from %08lx:", (unsigned long)stack);
+	printk("%sStack from %08lx:", loglvl, (unsigned long)stack);
 	for (i = 0; i < kstack_depth_to_print; i++) {
 		if (((unsigned long)stack & (THREAD_SIZE - 1)) >=
 		    THREAD_SIZE-4)
 			break;
 		if (i % 8 == 0)
-			pr_info(" ");
+			printk("%s ", loglvl);
 		pr_cont(" %08lx", *stack++);
 	}
 
-	pr_info("\nCall Trace:\n");
+	printk("%s\nCall Trace:\n", loglvl);
 	i = 0;
 	stack = esp;
 	while (((unsigned long)stack & (THREAD_SIZE - 1)) < THREAD_SIZE-4) {

@@ -150,10 +151,15 @@ void show_stack(struct task_struct *task, unsigned long *esp)
 		 */
 		if (check_kernel_text(addr)) {
 			if (i % 4 == 0)
-				pr_info("       ");
+				printk("%s       ", loglvl);
 			pr_cont(" [<%08lx>]", addr);
 			i++;
 		}
 	}
-	pr_info("\n");
+	printk("%s\n", loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *esp)
+{
+	show_stack_loglvl(task, esp, KERN_INFO);
 }

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:38 UTC #16 lore raw

PATCH v2 14/50 hexagon: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

As a good side-effect die() now prints the stacktrace with KERN_EMERG aligned with other messages.

Cc: Brian Cain <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/hexagon/kernel/traps.c | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

arch/hexagon/kernel/traps.c +17 ~~-14~~

index 69c623b14ddd..a8a3a210d781 100644
@@ -79,7 +79,7 @@ static const char *ex_name(int ex)
 }
 
 static void do_show_stack(struct task_struct *task, unsigned long *fp,
-			  unsigned long ip)
+			  unsigned long ip, const char *loglvl)
 {
 	int kstack_depth_to_print = 24;
 	unsigned long offset, size;

@@ -93,9 +93,8 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 	if (task == NULL)
 		task = current;
 
-	printk(KERN_INFO "CPU#%d, %s/%d, Call Trace:\n",
-	       raw_smp_processor_id(), task->comm,
-	       task_pid_nr(task));
+	printk("%sCPU#%d, %s/%d, Call Trace:\n", loglvl, raw_smp_processor_id(),
+		task->comm, task_pid_nr(task));
 
 	if (fp == NULL) {
 		if (task == current) {

@@ -108,7 +107,7 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 	}
 
 	if ((((unsigned long) fp) & 0x3) || ((unsigned long) fp < 0x1000)) {
-		printk(KERN_INFO "-- Corrupt frame pointer %p\n", fp);
+		printk("%s-- Corrupt frame pointer %p\n", loglvl, fp);
 		return;
 	}

@@ -125,8 +124,7 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 
 		name = kallsyms_lookup(ip, &size, &offset, &modname, tmpstr);
 
-		printk(KERN_INFO "[%p] 0x%lx: %s + 0x%lx", fp, ip, name,
-			offset);
+		printk("%s[%p] 0x%lx: %s + 0x%lx", loglvl, fp, ip, name, offset);
 		if (((unsigned long) fp < low) || (high < (unsigned long) fp))
 			printk(KERN_CONT " (FP out of bounds!)");
 		if (modname)

@@ -136,8 +134,7 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 		newfp = (unsigned long *) *fp;
 
 		if (((unsigned long) newfp) & 0x3) {
-			printk(KERN_INFO "-- Corrupt frame pointer %p\n",
-				newfp);
+			printk("%s-- Corrupt frame pointer %p\n", loglvl, newfp);
 			break;
 		}

@@ -147,7 +144,7 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 						+ 8);
 
 			if (regs->syscall_nr != -1) {
-				printk(KERN_INFO "-- trap0 -- syscall_nr: %ld",
+				printk("%s-- trap0 -- syscall_nr: %ld", loglvl,
 					regs->syscall_nr);
 				printk(KERN_CONT "  psp: %lx  elr: %lx\n",
 					 pt_psp(regs), pt_elr(regs));

@@ -155,7 +152,7 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 			} else {
 				/* really want to see more ... */
 				kstack_depth_to_print += 6;
-				printk(KERN_INFO "-- %s (0x%lx)  badva: %lx\n",
+				printk("%s-- %s (0x%lx)  badva: %lx\n", loglvl,
 					ex_name(pt_cause(regs)), pt_cause(regs),
 					pt_badva(regs));
 			}

@@ -178,10 +175,16 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 	}
 }
 
-void show_stack(struct task_struct *task, unsigned long *fp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *fp,
+		       const char *loglvl)
 {
 	/* Saved link reg is one word above FP */
-	do_show_stack(task, fp, 0);
+	do_show_stack(task, fp, 0, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *fp)
+{
+	show_stack_loglvl(task, fp, 0, KERN_INFO);
 }
 
 int die(const char *str, struct pt_regs *regs, long err)

@@ -207,7 +210,7 @@ int die(const char *str, struct pt_regs *regs, long err)
 
 	print_modules();
 	show_regs(regs);
-	do_show_stack(current, &regs->r30, pt_elr(regs));
+	do_show_stack(current, &regs->r30, pt_elr(regs), KERN_EMERG);
 
 	bust_spinlocks(0);
 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);

Signature · 1 line

2.25.1

Brian Cain

Acked-by on v2 14/50

2020-03-17 15:34 UTC #17 lore raw

RE: [PATCHv2 14/50] hexagon: Add show_stack_loglvl()

Acked-by Brian Cain <[email protected]>

Quoted 55 lines

Cc: Brian Cain <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-
[email protected]/T/#u

---
 arch/hexagon/kernel/traps.c | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

arch/hexagon/kernel/traps.c +3 -4

index 69c623b14ddd..a8a3a210d781 100644
@@ -79,7 +79,7 @@ static const char *ex_name(int ex)  }
 
 static void do_show_stack(struct task_struct *task, unsigned long *fp,
-			  unsigned long ip)
+			  unsigned long ip, const char *loglvl)
 {
 	int kstack_depth_to_print = 24;
 	unsigned long offset, size;

@@ -93,9 +93,8 @@ static void do_show_stack(struct task_struct *task,
 unsigned long *fp,
 	if (task == NULL)
 		task = current;
 
-	printk(KERN_INFO "CPU#%d, %s/%d, Call Trace:\n",
-	       raw_smp_processor_id(), task->comm,
-	       task_pid_nr(task));
+	printk("%sCPU#%d, %s/%d, Call Trace:\n", loglvl,
 raw_smp_processor_id(),
+		task->comm, task_pid_nr(task));

arch/hexagon/kernel/traps.c +2 -3

 	if (fp == NULL) {
 		if (task == current) {

@@ -108,7 +107,7 @@ static void do_show_stack(struct task_struct *task,
 unsigned long *fp,
 	}
 
 	if ((((unsigned long) fp) & 0x3) || ((unsigned long) fp < 0x1000)) {
-		printk(KERN_INFO "-- Corrupt frame pointer %p\n", fp);
+		printk("%s-- Corrupt frame pointer %p\n", loglvl, fp);
 		return;
 	}

@@ -125,8 +124,7 @@ static void do_show_stack(struct task_struct *task,
 unsigned long *fp,
 
 		name = kallsyms_lookup(ip, &size, &offset, &modname,
 tmpstr);
 
-		printk(KERN_INFO "[%p] 0x%lx: %s + 0x%lx", fp, ip, name,
-			offset);
+		printk("%s[%p] 0x%lx: %s + 0x%lx", loglvl, fp, ip, name,
 offset);

Quoted 1 line

if (((unsigned long) fp < low) || (high < (unsigned long)

fp))

Quoted 15 lines

arch/hexagon/kernel/traps.c +1 -2

 			printk(KERN_CONT " (FP out of bounds!)");
 		if (modname)

@@ -136,8 +134,7 @@ static void do_show_stack(struct task_struct *task,
 unsigned long *fp,
 		newfp = (unsigned long *) *fp;
 
 		if (((unsigned long) newfp) & 0x3) {
-			printk(KERN_INFO "-- Corrupt frame pointer %p\n",
-				newfp);
+			printk("%s-- Corrupt frame pointer %p\n", loglvl,
 newfp);
 			break;

arch/hexagon/kernel/traps.c +0 -0

arch/hexagon/kernel/traps.c static void do_show_stack(struct task_struct *task, · line 149

Quoted 7 lines

arch/hexagon/kernel/traps.c +1 -1

@@ -147,7 +144,7 @@ static void do_show_stack(struct task_struct *task,
 unsigned long *fp,
 						+ 8);
 
 			if (regs->syscall_nr != -1) {
-				printk(KERN_INFO "-- trap0 -- syscall_nr:
 %ld",
+				printk("%s-- trap0 -- syscall_nr: %ld",

loglvl,

arch/hexagon/kernel/traps.c static void do_show_stack(struct task_struct *task, · line 157

Quoted 11 lines

arch/hexagon/kernel/traps.c +0 -0

 					regs->syscall_nr);

arch/hexagon/kernel/traps.c +1 -1

 				printk(KERN_CONT "  psp: %lx  elr: %lx\n",
 					 pt_psp(regs), pt_elr(regs));

@@ -155,7 +152,7 @@ static void do_show_stack(struct task_struct *task,
 unsigned long *fp,
 			} else {
 				/* really want to see more ... */
 				kstack_depth_to_print += 6;
-				printk(KERN_INFO "-- %s (0x%lx)  badva:
 %lx\n",
+				printk("%s-- %s (0x%lx)  badva: %lx\n",

loglvl,

Quoted 34 lines

arch/hexagon/kernel/traps.c +0 -0

 					ex_name(pt_cause(regs)),

pt_cause(regs),

arch/hexagon/kernel/traps.c +7 -2

 					pt_badva(regs));
 			}

@@ -178,10 +175,16 @@ static void do_show_stack(struct task_struct
 *task, unsigned long *fp,
 	}
 }
 
-void show_stack(struct task_struct *task, unsigned long *fp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *fp,
+		       const char *loglvl)
 {
 	/* Saved link reg is one word above FP */
-	do_show_stack(task, fp, 0);
+	do_show_stack(task, fp, 0, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *fp) {
+	show_stack_loglvl(task, fp, 0, KERN_INFO);
 }
 
 int die(const char *str, struct pt_regs *regs, long err) @@ -207,7 +210,7

@@ int die(const char *str, struct pt_regs *regs, long err)

arch/hexagon/kernel/traps.c +1 -2

 	print_modules();
 	show_regs(regs);
-	do_show_stack(current, &regs->r30, pt_elr(regs));
+	do_show_stack(current, &regs->r30, pt_elr(regs), KERN_EMERG);
 
 	bust_spinlocks(0);
 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
--

2.25.1

Dmitry Safonov

author

2020-03-16 14:38 UTC #18 lore raw

PATCH v2 15/50 ia64: Pass log level as arg into ia64_do_show_stack()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Add log level argument to ia64_do_show_stack() as a preparation to introduce show_stack_loglvl().
Also, make ia64_do_show_stack() static as it's not used outside.

Cc: Fenghua Yu <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/ia64/include/asm/ptrace.h |  1 -
 arch/ia64/kernel/process.c     | 13 +++++++------
 2 files changed, 7 insertions(+), 7 deletions(-)

arch/ia64/include/asm/ptrace.h +0 -1

index 7ff574d56429..b3aa46090101 100644
@@ -114,7 +114,6 @@ static inline long regs_return_value(struct pt_regs *regs)
   struct task_struct;			/* forward decl */
   struct unw_frame_info;		/* forward decl */
 
-  extern void ia64_do_show_stack (struct unw_frame_info *, void *);
   extern unsigned long ia64_get_user_rbs_end (struct task_struct *, struct pt_regs *,
 					      unsigned long *);
   extern long ia64_peek (struct task_struct *, struct switch_stack *, unsigned long,

arch/ia64/kernel/process.c +7 -6

index 968b5f33e725..0526cc51ff0b 100644
@@ -64,12 +64,13 @@ EXPORT_SYMBOL(boot_option_idle_override);
 void (*pm_power_off) (void);
 EXPORT_SYMBOL(pm_power_off);
 
-void
+static void
 ia64_do_show_stack (struct unw_frame_info *info, void *arg)
 {
 	unsigned long ip, sp, bsp;
+	const char *loglvl = arg;
 
-	printk("\nCall Trace:\n");
+	printk("%s\nCall Trace:\n", loglvl);
 	do {
 		unw_get_ip(info, &ip);
 		if (ip = 0)

@@ -77,9 +78,9 @@ ia64_do_show_stack (struct unw_frame_info *info, void *arg)
 
 		unw_get_sp(info, &sp);
 		unw_get_bsp(info, &bsp);
-		printk(" [<%016lx>] %pS\n"
+		printk("%s [<%016lx>] %pS\n"
 			 "                                sp=%016lx bsp=%016lx\n",
-			 ip, (void *)ip, sp, bsp);
+			 loglvl, ip, (void *)ip, sp, bsp);
 	} while (unw_unwind(info) >= 0);
 }

@@ -87,12 +88,12 @@ void
 show_stack (struct task_struct *task, unsigned long *sp)
 {
 	if (!task)
-		unw_init_running(ia64_do_show_stack, NULL);
+		unw_init_running(ia64_do_show_stack, (void *)KERN_DEFAULT);
 	else {
 		struct unw_frame_info info;
 
 		unw_init_from_blocked_task(&info, task);
-		ia64_do_show_stack(&info, NULL);
+		ia64_do_show_stack(&info, (void *)KERN_DEFAULT);
 	}
 }

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:38 UTC #19 lore raw

PATCH v2 16/50 ia64: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Fenghua Yu <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/ia64/kernel/process.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

arch/ia64/kernel/process.c +10 -3

index 0526cc51ff0b..b0eeb19bdd8d 100644
@@ -85,18 +85,25 @@ ia64_do_show_stack (struct unw_frame_info *info, void *arg)
 }
 
 void
-show_stack (struct task_struct *task, unsigned long *sp)
+show_stack_loglvl (struct task_struct *task, unsigned long *sp,
+		   const char *loglvl)
 {
 	if (!task)
-		unw_init_running(ia64_do_show_stack, (void *)KERN_DEFAULT);
+		unw_init_running(ia64_do_show_stack, (void *)loglvl);
 	else {
 		struct unw_frame_info info;
 
 		unw_init_from_blocked_task(&info, task);
-		ia64_do_show_stack(&info, (void *)KERN_DEFAULT);
+		ia64_do_show_stack(&info, (void *)loglvl);
 	}
 }
 
+void
+show_stack (struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT);
+}
+
 void
 show_regs (struct pt_regs *regs)
 {

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:41 UTC #20 lore raw

PATCH v2 17/50 m68k: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Geert Uytterhoeven <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/m68k/kernel/traps.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

arch/m68k/kernel/traps.c +11 -5

index 344f93d36a9a..ffcc5ec4fac3 100644
@@ -811,13 +811,13 @@ asmlinkage void buserr_c(struct frame *fp)
 
 static int kstack_depth_to_print = 48;
 
-void show_trace(unsigned long *stack)
+static void show_trace(unsigned long *stack, const char *loglvl)
 {
 	unsigned long *endstack;
 	unsigned long addr;
 	int i;
 
-	pr_info("Call Trace:");
+	printk("%sCall Trace:", loglvl);
 	addr = (unsigned long)stack + THREAD_SIZE - 1;
 	endstack = (unsigned long *)(addr & -THREAD_SIZE);
 	i = 0;

@@ -935,7 +935,8 @@ void show_registers(struct pt_regs *regs)
 	pr_cont("\n");
 }
 
-void show_stack(struct task_struct *task, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+		       const char *loglvl)
 {
 	unsigned long *p;
 	unsigned long *endstack;

@@ -949,7 +950,7 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 	}
 	endstack = (unsigned long *)(((unsigned long)stack + THREAD_SIZE - 1) & -THREAD_SIZE);
 
-	pr_info("Stack from %08lx:", (unsigned long)stack);
+	printk("%sStack from %08lx:", loglvl, (unsigned long)stack);
 	p = stack;
 	for (i = 0; i < kstack_depth_to_print; i++) {
 		if (p + 1 > endstack)

@@ -959,7 +960,12 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 		pr_cont(" %08lx", *p++);
 	}
 	pr_cont("\n");
-	show_trace(stack);
+	show_trace(stack, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *stack)
+{
+	show_stack_loglvl(task, stack, KERN_INFO);
 }
 
 /*

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:41 UTC #21 lore raw

PATCH v2 18/50 microblaze: Add loglvl to microblaze_unwind_inner()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Add log level argument to microblaze_unwind_inner() as a preparation for introducing show_stack_loglvl().

Cc: Michal Simek <[email protected]>
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/microblaze/kernel/unwind.c | 38 ++++++++++++++++++++-------------
 1 file changed, 23 insertions(+), 15 deletions(-)

arch/microblaze/kernel/unwind.c +23 ~~-15~~

index 4241cdd28ee7..804bf0c99d8b 100644
@@ -154,7 +154,8 @@ static int lookup_prev_stack_frame(unsigned long fp, unsigned long pc,
 static void microblaze_unwind_inner(struct task_struct *task,
 				    unsigned long pc, unsigned long fp,
 				    unsigned long leaf_return,
-				    struct stack_trace *trace);
+				    struct stack_trace *trace,
+				    const char *loglvl);
 
 /**
  * unwind_trap - Unwind through a system trap, that stored previous state

@@ -162,16 +163,18 @@ static void microblaze_unwind_inner(struct task_struct *task,
  */
 #ifdef CONFIG_MMU
 static inline void unwind_trap(struct task_struct *task, unsigned long pc,
-				unsigned long fp, struct stack_trace *trace)
+				unsigned long fp, struct stack_trace *trace,
+				const char *loglvl)
 {
 	/* To be implemented */
 }
 #else
 static inline void unwind_trap(struct task_struct *task, unsigned long pc,
-				unsigned long fp, struct stack_trace *trace)
+				unsigned long fp, struct stack_trace *trace,
+				const char *loglvl)
 {
 	const struct pt_regs *regs = (const struct pt_regs *) fp;
-	microblaze_unwind_inner(task, regs->pc, regs->r1, regs->r15, trace);
+	microblaze_unwind_inner(task, regs->pc, regs->r1, regs->r15, trace, loglvl);
 }
 #endif

@@ -184,11 +187,13 @@ static inline void unwind_trap(struct task_struct *task, unsigned long pc,
  *				  the caller's return address.
  * @trace : Where to store stack backtrace (PC values).
  *	    NULL == print backtrace to kernel log
+ * @loglvl : Used for printk log level if (trace == NULL).
  */
 static void microblaze_unwind_inner(struct task_struct *task,
 			     unsigned long pc, unsigned long fp,
 			     unsigned long leaf_return,
-			     struct stack_trace *trace)
+			     struct stack_trace *trace,
+			     const char *loglvl)
 {
 	int ofs = 0;

@@ -214,11 +219,11 @@ static void microblaze_unwind_inner(struct task_struct *task,
 			const struct pt_regs *regs =
 				(const struct pt_regs *) fp;
 #endif
-			pr_info("HW EXCEPTION\n");
+			printk("%sHW EXCEPTION\n", loglvl);
 #ifndef CONFIG_MMU
 			microblaze_unwind_inner(task, regs->r17 - 4,
 						fp + EX_HANDLER_STACK_SIZ,
-						regs->r15, trace);
+						regs->r15, trace, loglvl);
 #endif
 			return;
 		}

@@ -228,8 +233,8 @@ static void microblaze_unwind_inner(struct task_struct *task,
 			if ((return_to >= handler->start_addr)
 			    && (return_to <= handler->end_addr)) {
 				if (!trace)
-					pr_info("%s\n", handler->trap_name);
-				unwind_trap(task, pc, fp, trace);
+					printk("%s%s\n", loglvl, handler->trap_name);
+				unwind_trap(task, pc, fp, trace, loglvl);
 				return;
 			}
 		}

@@ -248,13 +253,13 @@ static void microblaze_unwind_inner(struct task_struct *task,
 		} else {
 			/* Have we reached userland? */
 			if (unlikely(pc == task_pt_regs(task)->pc)) {
-				pr_info("[<%p>] PID %lu [%s]\n",
-					(void *) pc,
+				printk("%s[<%p>] PID %lu [%s]\n",
+					loglvl, (void *) pc,
 					(unsigned long) task->pid,
 					task->comm);
 				break;
 			} else
-				print_ip_sym(KERN_INFO, pc);
+				print_ip_sym(loglvl, pc);
 		}
 
 		/* Stop when we reach anything not part of the kernel */

@@ -285,11 +290,13 @@ static void microblaze_unwind_inner(struct task_struct *task,
  */
 void microblaze_unwind(struct task_struct *task, struct stack_trace *trace)
 {
+	const char *loglvl = KERN_INFO;
+
 	if (task) {
 		if (task == current) {
 			const struct pt_regs *regs = task_pt_regs(task);
 			microblaze_unwind_inner(task, regs->pc, regs->r1,
-						regs->r15, trace);
+						regs->r15, trace, loglvl);
 		} else {
 			struct thread_info *thread_info =
 				(struct thread_info *)(task->stack);

@@ -299,7 +306,8 @@ void microblaze_unwind(struct task_struct *task, struct stack_trace *trace)
 			microblaze_unwind_inner(task,
 						(unsigned long) &_switch_to,
 						cpu_context->r1,
-						cpu_context->r15, trace);
+						cpu_context->r15,
+						trace, loglvl);
 		}
 	} else {
 		unsigned long pc, fp;

@@ -314,7 +322,7 @@ void microblaze_unwind(struct task_struct *task, struct stack_trace *trace)
 		);
 
 		/* Since we are not a leaf function, use leaf_return = 0 */
-		microblaze_unwind_inner(current, pc, fp, 0, trace);
+		microblaze_unwind_inner(current, pc, fp, 0, trace, loglvl);
 	}
 }

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:41 UTC #22 lore raw

PATCH v2 19/50 microblaze: Add loglvl to microblaze_unwind()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Add log level parameter to microblaze_unwind() as a preparation to add show_stack_loglvl().

Cc: Michal Simek <[email protected]>
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/microblaze/include/asm/unwind.h | 3 ++-
 arch/microblaze/kernel/stacktrace.c  | 4 ++--
 arch/microblaze/kernel/traps.c       | 2 +-
 arch/microblaze/kernel/unwind.c      | 6 +++---
 4 files changed, 8 insertions(+), 7 deletions(-)

arch/microblaze/include/asm/unwind.h +2 -1

index d248b7de4b13..7c28f8d5a243 100644
@@ -23,7 +23,8 @@ extern struct trap_handler_info microblaze_trap_handlers;
 extern const char _hw_exception_handler;
 extern const char ex_handler_unhandled;
 
-void microblaze_unwind(struct task_struct *task, struct stack_trace *trace);
+void microblaze_unwind(struct task_struct *task, struct stack_trace *trace,
+		       const char *loglvl);
 
 #endif	/* __MICROBLAZE_UNWIND_H */

arch/microblaze/kernel/stacktrace.c +2 -2

index b4debe283a79..b266c4d6ed9d 100644
@@ -20,12 +20,12 @@ void save_stack_trace(struct stack_trace *trace)
 {
 	/* Exclude our helper functions from the trace*/
 	trace->skip += 2;
-	microblaze_unwind(NULL, trace);
+	microblaze_unwind(NULL, trace, "");
 }
 EXPORT_SYMBOL_GPL(save_stack_trace);
 
 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 {
-	microblaze_unwind(tsk, trace);
+	microblaze_unwind(tsk, trace, "");
 }
 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);

arch/microblaze/kernel/traps.c +1 -1

index 45bbba9d919f..be726ee120fb 100644
@@ -68,7 +68,7 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 	print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 32, 4, (void *)fp,
 		       words_to_show << 2, 0);
 	pr_info("\n\nCall Trace:\n");
-	microblaze_unwind(task, NULL);
+	microblaze_unwind(task, NULL, KERN_INFO);
 	pr_info("\n");
 
 	if (!task)

arch/microblaze/kernel/unwind.c +3 -3

index 804bf0c99d8b..778a761af0a7 100644
@@ -287,11 +287,11 @@ static void microblaze_unwind_inner(struct task_struct *task,
  * @task  : Task whose stack we are to unwind (NULL == current)
  * @trace : Where to store stack backtrace (PC values).
  *	    NULL == print backtrace to kernel log
+ * @loglvl : Used for printk log level if (trace == NULL).
  */
-void microblaze_unwind(struct task_struct *task, struct stack_trace *trace)
+void microblaze_unwind(struct task_struct *task, struct stack_trace *trace,
+		       const char *loglvl)
 {
-	const char *loglvl = KERN_INFO;
-
 	if (task) {
 		if (task == current) {
 			const struct pt_regs *regs = task_pt_regs(task);

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:41 UTC #23 lore raw

PATCH v2 20/50 microblaze: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Michal Simek <[email protected]>
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/microblaze/kernel/traps.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

arch/microblaze/kernel/traps.c +12 -6

index be726ee120fb..149ae534937e 100644
@@ -31,7 +31,8 @@ static int __init kstack_setup(char *s)
 }
 __setup("kstack=", kstack_setup);
 
-void show_stack(struct task_struct *task, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+		       const char *loglvl)
 {
 	unsigned long words_to_show;
 	u32 fp = (u32) sp;

@@ -50,7 +51,7 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 	if (kstack_depth_to_print && (words_to_show > kstack_depth_to_print))
 		words_to_show = kstack_depth_to_print;
 
-	pr_info("Kernel Stack:\n");
+	printk("%sKernel Stack:\n", loglvl);
 
 	/*
 	 * Make the first line an 'odd' size if necessary to get

@@ -65,14 +66,19 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 			words_to_show -= line1_words;
 		}
 	}
-	print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 32, 4, (void *)fp,
+	print_hex_dump(loglvl, "", DUMP_PREFIX_ADDRESS, 32, 4, (void *)fp,
 		       words_to_show << 2, 0);
-	pr_info("\n\nCall Trace:\n");
-	microblaze_unwind(task, NULL, KERN_INFO);
-	pr_info("\n");
+	printk("%s\n\nCall Trace:\n", loglvl);
+	microblaze_unwind(task, NULL, loglvl);
+	printk("%s\n", loglvl);
 
 	if (!task)
 		task = current;
 
 	debug_show_held_locks(task);
 }
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_INFO);
+}

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:41 UTC #24 lore raw

PATCH v2 21/50 mips: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: James Hogan <[email protected]>
Cc: Paul Burton <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/mips/kernel/traps.c | 41 +++++++++++++++++++++++-----------------
 1 file changed, 24 insertions(+), 17 deletions(-)

arch/mips/kernel/traps.c +24 ~~-17~~

index de05503c680c..077aabbd6b9f 100644
@@ -106,26 +106,26 @@ void (*board_bind_eic_interrupt)(int irq, int regset);
 void (*board_ebase_setup)(void);
 void(*board_cache_error_setup)(void);
 
-static void show_raw_backtrace(unsigned long reg29)
+static void show_raw_backtrace(unsigned long reg29, const char *loglvl)
 {
 	unsigned long *sp = (unsigned long *)(reg29 & ~3);
 	unsigned long addr;
 
-	printk("Call Trace:");
+	printk("%sCall Trace:", loglvl);
 #ifdef CONFIG_KALLSYMS
-	printk("\n");
+	printk("%s\n", loglvl);
 #endif
 	while (!kstack_end(sp)) {
 		unsigned long __user *p =
 			(unsigned long __user *)(unsigned long)sp++;
 		if (__get_user(addr, p)) {
-			printk(" (Bad stack address)");
+			printk("%s (Bad stack address)", loglvl);
 			break;
 		}
 		if (__kernel_text_address(addr))
-			print_ip_sym(KERN_DEFAULT, addr);
+			print_ip_sym(loglvl, addr);
 	}
-	printk("\n");
+	printk("%s\n", loglvl);
 }
 
 #ifdef CONFIG_KALLSYMS

@@ -138,7 +138,8 @@ static int __init set_raw_show_trace(char *str)
 __setup("raw_show_trace", set_raw_show_trace);
 #endif
 
-static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
+static void show_backtrace(struct task_struct *task, const struct pt_regs *regs,
+			   const char *loglvl)
 {
 	unsigned long sp = regs->regs[29];
 	unsigned long ra = regs->regs[31];

@@ -148,12 +149,12 @@ static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
 		task = current;
 
 	if (raw_show_trace || user_mode(regs) || !__kernel_text_address(pc)) {
-		show_raw_backtrace(sp);
+		show_raw_backtrace(sp, loglvl);
 		return;
 	}
-	printk("Call Trace:\n");
+	printk("%sCall Trace:\n", loglvl);
 	do {
-		print_ip_sym(KERN_DEFAULT, pc);
+		print_ip_sym(loglvl, pc);
 		pc = unwind_stack(task, &sp, pc, &ra);
 	} while (pc);
 	pr_cont("\n");

@@ -164,19 +165,19 @@ static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
  * with at least a bit of error checking ...
  */
 static void show_stacktrace(struct task_struct *task,
-	const struct pt_regs *regs)
+	const struct pt_regs *regs, const char *loglvl)
 {
 	const int field = 2 * sizeof(unsigned long);
 	long stackdata;
 	int i;
 	unsigned long __user *sp = (unsigned long __user *)regs->regs[29];
 
-	printk("Stack :");
+	printk("%sStack :", loglvl);
 	i = 0;
 	while ((unsigned long) sp & (PAGE_SIZE - 1)) {
 		if (i && ((i % (64 / field)) == 0)) {
 			pr_cont("\n");
-			printk("       ");
+			printk("%s       ", loglvl);
 		}
 		if (i > 39) {
 			pr_cont(" ...");

@@ -192,10 +193,11 @@ static void show_stacktrace(struct task_struct *task,
 		i++;
 	}
 	pr_cont("\n");
-	show_backtrace(task, regs);
+	show_backtrace(task, regs, loglvl);
 }
 
-void show_stack(struct task_struct *task, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+		       const char *loglvl)
 {
 	struct pt_regs regs;
 	mm_segment_t old_fs = get_fs();

@@ -219,10 +221,15 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 	 * the stack in the kernel (not user) address space.
 	 */
 	set_fs(KERNEL_DS);
-	show_stacktrace(task, &regs);
+	show_stacktrace(task, &regs, loglvl);
 	set_fs(old_fs);
 }
 
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT)
+}
+
 static void show_code(unsigned int __user *pc)
 {
 	long i;

@@ -371,7 +378,7 @@ void show_registers(struct pt_regs *regs)
 	if (!user_mode(regs))
 		/* Necessary for getting the correct stack content */
 		set_fs(KERNEL_DS);
-	show_stacktrace(current, regs);
+	show_stacktrace(current, regs, KERN_DEFAULT);
 	show_code((unsigned int __user *) regs->cp0_epc);
 	printk("\n");
 	set_fs(old_fs);

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:41 UTC #25 lore raw

PATCH v2 22/50 nds32: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Greentime Hu <[email protected]>
Cc: Vincent Chen <[email protected]>
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/nds32/kernel/traps.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

arch/nds32/kernel/traps.c +14 -7

index 40625760a125..90f12582c218 100644
@@ -97,18 +97,19 @@ static void dump_instr(struct pt_regs *regs)
 }
 
 #define LOOP_TIMES (100)
-static void __dump(struct task_struct *tsk, unsigned long *base_reg)
+static void __dump(struct task_struct *tsk, unsigned long *base_reg,
+		   const char *loglvl)
 {
 	unsigned long ret_addr;
 	int cnt = LOOP_TIMES, graph = 0;
-	pr_emerg("Call Trace:\n");
+	printk("%sCall Trace:\n", loglvl);
 	if (!IS_ENABLED(CONFIG_FRAME_POINTER)) {
 		while (!kstack_end(base_reg)) {
 			ret_addr = *base_reg++;
 			if (__kernel_text_address(ret_addr)) {
 				ret_addr = ftrace_graph_ret_addr(
 						tsk, &graph, ret_addr, NULL);
-				print_ip_sym(KERN_EMERG, ret_addr);
+				print_ip_sym(loglvl, ret_addr);
 			}
 			if (--cnt < 0)
 				break;

@@ -124,17 +125,18 @@ static void __dump(struct task_struct *tsk, unsigned long *base_reg)
 
 				ret_addr = ftrace_graph_ret_addr(
 						tsk, &graph, ret_addr, NULL);
-				print_ip_sym(KERN_EMERG, ret_addr);
+				print_ip_sym(loglvl, ret_addr);
 			}
 			if (--cnt < 0)
 				break;
 			base_reg = (unsigned long *)next_fp;
 		}
 	}
-	pr_emerg("\n");
+	printk("%s\n", loglvl);
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
+		       const char *loglvl)
 {
 	unsigned long *base_reg;

@@ -151,10 +153,15 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
 		else
 			__asm__ __volatile__("\tori\t%0, $fp, #0\n":"=r"(base_reg));
 	}
-	__dump(tsk, base_reg);
+	__dump(tsk, base_reg, loglvl);
 	barrier();
 }
 
+void show_stack(struct task_struct *tsk, unsigned long *sp)
+{
+	show_stack_loglvl(tsk, sp, KERN_EMERG);
+}
+
 DEFINE_SPINLOCK(die_lock);
 
 /*

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:41 UTC #26 lore raw

PATCH v2 23/50 nios2: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Ley Foon Tan <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/nios2/kernel/traps.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

arch/nios2/kernel/traps.c +15 -8

index 486db793923c..08071caa9b36 100644
@@ -52,12 +52,14 @@ void _exception(int signo, struct pt_regs *regs, int code, unsigned long addr)
 }
 
 /*
- * The show_stack is an external API which we do not use ourselves.
+ * The show_stack(), show_stack_loglvl() are external API
+ * which we do not use ourselves.
  */
 
 int kstack_depth_to_print = 48;
 
-void show_stack(struct task_struct *task, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+		       const char *loglvl)
 {
 	unsigned long *endstack, addr;
 	int i;

@@ -72,16 +74,16 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 	addr = (unsigned long) stack;
 	endstack = (unsigned long *) PAGE_ALIGN(addr);
 
-	pr_emerg("Stack from %08lx:", (unsigned long)stack);
+	printk("%sStack from %08lx:", loglvl, (unsigned long)stack);
 	for (i = 0; i < kstack_depth_to_print; i++) {
 		if (stack + 1 > endstack)
 			break;
 		if (i % 8 == 0)
-			pr_emerg("\n       ");
-		pr_emerg(" %08lx", *stack++);
+			printk("%s\n       ", loglvl);
+		printk("%s %08lx", loglvl, *stack++);
 	}
 
-	pr_emerg("\nCall Trace:");
+	printk("%s\nCall Trace:", loglvl);
 	i = 0;
 	while (stack + 1 <= endstack) {
 		addr = *stack++;

@@ -97,11 +99,16 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 		     (addr <= (unsigned long) _etext))) {
 			if (i % 4 == 0)
 				pr_emerg("\n       ");
-			pr_emerg(" [<%08lx>]", addr);
+			printk("%s [<%08lx>]", loglvl, addr);
 			i++;
 		}
 	}
-	pr_emerg("\n");
+	printk("%s\n", loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *stack)
+{
+	show_stack_loglvl(task, stack, KERN_EMERG);
 }
 
 void __init trap_init(void)

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:38 UTC #27 lore raw

PATCH v2 24/50 openrisc: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Jonas Bonn <[email protected]>
Cc: Stafford Horne <[email protected]>
Cc: Stefan Kristiansson <[email protected]>
Cc: openrisc at lists.librecores.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima at arista.com/T/#u

---
 arch/openrisc/kernel/traps.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

arch/openrisc/kernel/traps.c +12 -4

index 932a8ec2b520..9d5a85dd1992 100644
@@ -41,18 +41,26 @@ unsigned long __user *lwa_addr;
 
 void print_trace(void *data, unsigned long addr, int reliable)
 {
-	pr_emerg("[<%p>] %s%pS\n", (void *) addr, reliable ? "" : "? ",
+	const char *loglvl = data;
+
+	printk("%s[<%p>] %s%pS\n", loglvl, (void *) addr, reliable ? "" : "? ",
 	       (void *) addr);
 }
 
 /* displays a short stack trace */
-void show_stack(struct task_struct *task, unsigned long *esp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *esp,
+		const char *loglvl)
 {
 	if (esp == NULL)
 		esp = (unsigned long *)&esp;
 
-	pr_emerg("Call trace:\n");
-	unwind_stack(NULL, esp, print_trace);
+	printk("%sCall trace:\n", loglvl);
+	unwind_stack((void *)loglvl, esp, print_trace);
+}
+
+void show_stack(struct task_struct *task, unsigned long *esp)
+{
+	show_stack_loglvl(task, esp, KERN_EMERG);
 }
 
 void show_trace_task(struct task_struct *tsk)

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:41 UTC #28 lore raw

PATCH v2 25/50 parisc: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Helge Deller <[email protected]>
Cc: "James E.J. Bottomley" <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/parisc/kernel/traps.c | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

arch/parisc/kernel/traps.c +17 ~~-11~~

index 82fc01189488..c2411de3730f 100644
@@ -49,7 +49,7 @@
 #include "../math-emu/math-emu.h"	/* for handle_fpe() */
 
 static void parisc_show_stack(struct task_struct *task,
-	struct pt_regs *regs);
+	struct pt_regs *regs, const char *loglvl);
 
 static int printbinary(char *buf, unsigned long x, int nbits)
 {

@@ -155,7 +155,7 @@ void show_regs(struct pt_regs *regs)
 		printk("%s IAOQ[1]: %pS\n", level, (void *) regs->iaoq[1]);
 		printk("%s RP(r2): %pS\n", level, (void *) regs->gr[2]);
 
-		parisc_show_stack(current, regs);
+		parisc_show_stack(current, regs, KERN_DEFAULT);
 	}
 }

@@ -170,37 +170,43 @@ static DEFINE_RATELIMIT_STATE(_hppa_rs,
 }
 
 
-static void do_show_stack(struct unwind_frame_info *info)
+static void do_show_stack(struct unwind_frame_info *info, const char *loglvl)
 {
 	int i = 1;
 
-	printk(KERN_CRIT "Backtrace:\n");
+	printk("%sBacktrace:\n", loglvl);
 	while (i <= MAX_UNWIND_ENTRIES) {
 		if (unwind_once(info) < 0 || info->ip == 0)
 			break;
 
 		if (__kernel_text_address(info->ip)) {
-			printk(KERN_CRIT " [<" RFMT ">] %pS\n",
-				info->ip, (void *) info->ip);
+			printk("%s [<" RFMT ">] %pS\n",
+				loglvl, info->ip, (void *) info->ip);
 			i++;
 		}
 	}
-	printk(KERN_CRIT "\n");
+	printk("%s\n", loglvl);
 }
 
 static void parisc_show_stack(struct task_struct *task,
-	struct pt_regs *regs)
+	struct pt_regs *regs, const char *loglvl)
 {
 	struct unwind_frame_info info;
 
 	unwind_frame_init_task(&info, task, regs);
 
-	do_show_stack(&info);
+	do_show_stack(&info, loglvl);
+}
+
+void show_stack_loglvl(struct task_struct *t, unsigned long *sp,
+		       const char *loglvl)
+{
+	parisc_show_stack(t, NULL, loglvl);
 }
 
 void show_stack(struct task_struct *t, unsigned long *sp)
 {
-	parisc_show_stack(t, NULL);
+	show_stack_loglvl(t, sp, KERN_CRIT)
 }
 
 int is_valid_bugaddr(unsigned long iaoq)

@@ -446,7 +452,7 @@ void parisc_terminate(char *msg, struct pt_regs *regs, int code, unsigned long o
 		/* show_stack(NULL, (unsigned long *)regs->gr[30]); */
 		struct unwind_frame_info info;
 		unwind_frame_init(&info, current, regs);
-		do_show_stack(&info);
+		do_show_stack(&info, KERN_CRIT);
 	}
 
 	printk("\n");

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:41 UTC #29 lore raw

PATCH v2 26/50 powerpc: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

Acked-by Michael Ellerman <[email protected]> (powerpc)

---
 arch/powerpc/kernel/process.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

arch/powerpc/kernel/process.c +13 -5

index fad50db9dcf2..c1ab7f613da4 100644
@@ -2034,7 +2034,8 @@ unsigned long get_wchan(struct task_struct *p)
 
 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
 
-void show_stack(struct task_struct *tsk, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *stack,
+		       const char *loglvl)
 {
 	unsigned long sp, ip, lr, newsp;
 	int count = 0;

@@ -2059,7 +2060,7 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 	}
 
 	lr = 0;
-	printk("Call Trace:\n");
+	printk("%sCall Trace:\n", loglvl);
 	do {
 		if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
 			break;

@@ -2068,7 +2069,8 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 		newsp = stack[0];
 		ip = stack[STACK_FRAME_LR_SAVE];
 		if (!firstframe || ip != lr) {
-			printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
+			printk("%s["REG"] ["REG"] %pS",
+				loglvl, sp, ip, (void *)ip);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 			ret_addr = ftrace_graph_ret_addr(current,
 						&ftrace_idx, ip, stack);

@@ -2090,8 +2092,9 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 			struct pt_regs *regs = (struct pt_regs *)
 				(sp + STACK_FRAME_OVERHEAD);
 			lr = regs->link;
-			printk("--- interrupt: %lx at %pS\n    LR = %pS\n",
-			       regs->trap, (void *)regs->nip, (void *)lr);
+			printk("%s--- interrupt: %lx at %pS\n    LR = %pS\n",
+			       loglvl, regs->trap,
+			       (void *)regs->nip, (void *)lr);
 			firstframe = 1;
 		}

@@ -2101,6 +2104,11 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 	put_task_stack(tsk);
 }
 
+void show_stack(struct task_struct *tsk, unsigned long *stack)
+{
+	show_stack_loglvl(tsk, stack, KERN_DEFAULT);
+}
+
 #ifdef CONFIG_PPC64
 /* Called with hard IRQs off */
 void notrace __ppc64_runlatch_on(void)

Signature · 1 line

2.25.1

Michael Ellerman

reviewer Acked-by on v2 26/50

2020-03-19 04:03 UTC #30 lore raw

Re: [PATCHv2 26/50] powerpc: Add show_stack_loglvl()

Quoted 24 lines · Dmitry Safonov

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).
Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.
Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.
Introduce show_stack_loglvl(), that eventually will substitute show_stack().
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

Quoted 5 lines

Acked-by Michael Ellerman <[email protected]> (powerpc)
Signed-off-by Dmitry Safonov <[email protected]>
---
 arch/powerpc/kernel/process.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

Thanks for doing this, it has caused me problems in the past.

Acked-by Michael Ellerman <[email protected]> (powerpc)

cheers

Quoted 59 lines

arch/powerpc/kernel/process.c +13 -5

index fad50db9dcf2..c1ab7f613da4 100644
@@ -2034,7 +2034,8 @@ unsigned long get_wchan(struct task_struct *p)
 
 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
 
-void show_stack(struct task_struct *tsk, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *stack,
+		       const char *loglvl)
 {
 	unsigned long sp, ip, lr, newsp;
 	int count = 0;

@@ -2059,7 +2060,7 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 	}
 
 	lr = 0;
-	printk("Call Trace:\n");
+	printk("%sCall Trace:\n", loglvl);
 	do {
 		if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
 			break;

@@ -2068,7 +2069,8 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 		newsp = stack[0];
 		ip = stack[STACK_FRAME_LR_SAVE];
 		if (!firstframe || ip != lr) {
-			printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
+			printk("%s["REG"] ["REG"] %pS",
+				loglvl, sp, ip, (void *)ip);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 			ret_addr = ftrace_graph_ret_addr(current,
 						&ftrace_idx, ip, stack);

@@ -2090,8 +2092,9 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 			struct pt_regs *regs = (struct pt_regs *)
 				(sp + STACK_FRAME_OVERHEAD);
 			lr = regs->link;
-			printk("--- interrupt: %lx at %pS\n    LR = %pS\n",
-			       regs->trap, (void *)regs->nip, (void *)lr);
+			printk("%s--- interrupt: %lx at %pS\n    LR = %pS\n",
+			       loglvl, regs->trap,
+			       (void *)regs->nip, (void *)lr);
 			firstframe = 1;
 		}

@@ -2101,6 +2104,11 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 	put_task_stack(tsk);
 }
 
+void show_stack(struct task_struct *tsk, unsigned long *stack)
+{
+	show_stack_loglvl(tsk, stack, KERN_DEFAULT);
+}
+
 #ifdef CONFIG_PPC64
 /* Called with hard IRQs off */
 void notrace __ppc64_runlatch_on(void)

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:41 UTC #31 lore raw

PATCH v2 27/50 riscv: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Albert Ou <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/riscv/kernel/stacktrace.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

arch/riscv/kernel/stacktrace.c +10 -3

index a76892b48fff..5b414ba9848b 100644
@@ -98,16 +98,23 @@ static void notrace walk_stackframe(struct task_struct *task,
 
 static bool print_trace_address(unsigned long pc, void *arg)
 {
-	print_ip_sym(KERN_DEFAULT, pc);
+	const char *loglvl = arg;
+
+	print_ip_sym(loglvl, pc);
 	return false;
 }
 
-void show_stack(struct task_struct *task, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+		       const char *loglvl)
 {
 	pr_cont("Call Trace:\n");
-	walk_stackframe(task, NULL, print_trace_address, NULL);
+	walk_stackframe(task, NULL, print_trace_address, (void *)loglvl);
 }
 
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT);
+}
 
 static bool save_wchan(unsigned long pc, void *arg)
 {

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:41 UTC #32 lore raw

PATCH v2 28/50 s390: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Christian Borntraeger <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/s390/kernel/dumpstack.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

arch/s390/kernel/dumpstack.c +11 -5

index 2c122d8bab93..887a054919fc 100644
@@ -126,18 +126,24 @@ int get_stack_info(unsigned long sp, struct task_struct *task,
 	return -EINVAL;
 }
 
-void show_stack(struct task_struct *task, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+		       const char *loglvl)
 {
 	struct unwind_state state;
 
-	printk("Call Trace:\n");
+	printk("%sCall Trace:\n", loglvl);
 	unwind_for_each_frame(&state, task, NULL, (unsigned long) stack)
-		printk(state.reliable ? " [<%016lx>] %pSR \n" :
-					"([<%016lx>] %pSR)\n",
-		       state.ip, (void *) state.ip);
+		printk(state.reliable ? "%s [<%016lx>] %pSR \n" :
+					"%s([<%016lx>] %pSR)\n",
+		       loglvl, state.ip, (void *) state.ip);
 	debug_show_held_locks(task ? : current);
 }
 
+void show_stack(struct task_struct *task, unsigned long *stack)
+{
+	show_stack_loglvl(task, stack, KERN_DEFAULT);
+}
+
 static void show_last_breaking_event(struct pt_regs *regs)
 {
 	printk("Last Breaking-Event-Address:\n");

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:38 UTC #33 lore raw

PATCH v2 29/50 sh: Add loglvl to dump_mem()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Add log level argument to dump_mem() as a preparation to introduce show_stack_loglvl().

Cc: Rich Felker <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/sh/include/asm/kdebug.h |  3 ++-
 arch/sh/kernel/dumpstack.c   | 17 +++++++++--------
 arch/sh/kernel/traps.c       |  4 ++--
 3 files changed, 13 insertions(+), 11 deletions(-)

arch/sh/include/asm/kdebug.h +2 -1

index 5212f5fcd752..de8693fabb1d 100644
@@ -13,6 +13,7 @@ enum die_val {
 
 /* arch/sh/kernel/dumpstack.c */
 extern void printk_address(unsigned long address, int reliable);
-extern void dump_mem(const char *str, unsigned long bottom, unsigned long top);
+extern void dump_mem(const char *str, const char *loglvl,
+		     unsigned long bottom, unsigned long top);
 
 #endif /* __ASM_SH_KDEBUG_H */

arch/sh/kernel/dumpstack.c +9 -8

index 9f1c9c11d62d..6784b914fba0 100644
@@ -16,30 +16,31 @@
 #include <asm/unwinder.h>
 #include <asm/stacktrace.h>
 
-void dump_mem(const char *str, unsigned long bottom, unsigned long top)
+void dump_mem(const char *str, const char *loglvl,
+	      unsigned long bottom, unsigned long top)
 {
 	unsigned long p;
 	int i;
 
-	printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
+	printk("%s%s(0x%08lx to 0x%08lx)\n", loglvl, str, bottom, top);
 
 	for (p = bottom & ~31; p < top; ) {
-		printk("%04lx: ", p & 0xffff);
+		printk("%s%04lx: ", loglvl,  p & 0xffff);
 
 		for (i = 0; i < 8; i++, p += 4) {
 			unsigned int val;
 
 			if (p < bottom || p >= top)
-				printk("         ");
+				printk("%s         ", loglvl);
 			else {
 				if (__get_user(val, (unsigned int __user *)p)) {
-					printk("\n");
+					printk("%s\n", loglvl);
 					return;
 				}
-				printk("%08x ", val);
+				printk("%s%08x ", loglvl, val);
 			}
 		}
-		printk("\n");
+		printk("%s\n", loglvl);
 	}
 }

@@ -156,7 +157,7 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
 		sp = (unsigned long *)tsk->thread.sp;
 
 	stack = (unsigned long)sp;
-	dump_mem("Stack: ", stack, THREAD_SIZE +
+	dump_mem("Stack: ", KERN_DEFAULT, stack, THREAD_SIZE +
 		 (unsigned long)task_stack_page(tsk));
 	show_trace(tsk, sp, NULL);
 }

arch/sh/kernel/traps.c +2 -2

index 63cf17bc760d..faad65409075 100644
@@ -38,8 +38,8 @@ void die(const char *str, struct pt_regs *regs, long err)
 			task_pid_nr(current), task_stack_page(current) + 1);
 
 	if (!user_mode(regs) || in_interrupt())
-		dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
-			 (unsigned long)task_stack_page(current));
+		dump_mem("Stack: ", KERN_DEFAULT, regs->regs[15],
+			THREAD_SIZE + (unsigned long)task_stack_page(current));
 
 	notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:38 UTC #34 lore raw

PATCH v2 30/50 sh: Remove needless printk()

Currently `data' is always an empty line "".
No need for additional printk() call.

Cc Rich Felker <[email protected]>

Cc Yoshinori Sato <[email protected]>

---
 arch/sh/kernel/dumpstack.c | 1 -
 1 file changed, 1 deletion(-)

arch/sh/kernel/dumpstack.c +0 -1

index 6784b914fba0..2c1a78e5776b 100644
@@ -118,7 +118,6 @@ static int print_trace_stack(void *data, char *name)
  */
 static void print_trace_address(void *data, unsigned long addr, int reliable)
 {
-	printk("%s", (char *)data);
 	printk_address(addr, reliable);
 }

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:38 UTC #35 lore raw

PATCH v2 31/50 sh: Add loglvl to printk_address()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Add log level argument to printk_address() as a preparation to introduce show_stack_loglvl().

As a good side-effect show_fault_oops() now prints the address with KERN_EMREG as the rest of output, making sure there won't be situation where "PC: " is printed without actual address.

Cc: Rich Felker <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/sh/include/asm/kdebug.h | 3 ++-
 arch/sh/kernel/dumpstack.c   | 6 +++---
 arch/sh/mm/fault.c           | 2 +-
 3 files changed, 6 insertions(+), 5 deletions(-)

arch/sh/include/asm/kdebug.h +2 -1

index de8693fabb1d..960545306afa 100644
@@ -12,7 +12,8 @@ enum die_val {
 };
 
 /* arch/sh/kernel/dumpstack.c */
-extern void printk_address(unsigned long address, int reliable);
+extern void printk_address(unsigned long address, int reliable,
+			   const char *loglvl);
 extern void dump_mem(const char *str, const char *loglvl,
 		     unsigned long bottom, unsigned long top);

arch/sh/kernel/dumpstack.c +3 -3

index 2c1a78e5776b..959064b90055 100644
@@ -44,9 +44,9 @@ void dump_mem(const char *str, const char *loglvl,
 	}
 }
 
-void printk_address(unsigned long address, int reliable)
+void printk_address(unsigned long address, int reliable, const char *loglvl)
 {
-	printk(" [<%p>] %s%pS\n", (void *) address,
+	printk("%s [<%p>] %s%pS\n", loglvl, (void *) address,
 			reliable ? "" : "? ", (void *) address);
 }

@@ -118,7 +118,7 @@ static int print_trace_stack(void *data, char *name)
  */
 static void print_trace_address(void *data, unsigned long addr, int reliable)
 {
-	printk_address(addr, reliable);
+	printk_address(addr, reliable, (char *)data);
 }
 
 static const struct stacktrace_ops print_trace_ops = {

arch/sh/mm/fault.c +1 -1

index 5f51456f4fc7..b11f0c5e65b6 100644
@@ -196,7 +196,7 @@ show_fault_oops(struct pt_regs *regs, unsigned long address)
 
 	printk(KERN_CONT " at %08lx\n", address);
 	printk(KERN_ALERT "PC:");
-	printk_address(regs->pc, 1);
+	printk_address(regs->pc, 1, KERN_ALERT);
 
 	show_pte(NULL, address);
 }

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:38 UTC #36 lore raw

PATCH v2 32/50 sh: Add loglvl to show_trace()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Add log level parameter to show_trace() as a preparation to introduce show_stack_loglvl().

Cc: Rich Felker <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/sh/include/asm/processor_32.h |  2 +-
 arch/sh/kernel/dumpstack.c         | 10 +++++-----
 arch/sh/kernel/process_32.c        |  2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

arch/sh/include/asm/processor_32.h +1 -1

index 0e0ecc0132e3..d44409413418 100644
@@ -171,7 +171,7 @@ static __inline__ void enable_fpu(void)
 #define thread_saved_pc(tsk)	(tsk->thread.pc)
 
 void show_trace(struct task_struct *tsk, unsigned long *sp,
-		struct pt_regs *regs);
+		struct pt_regs *regs, const char *loglvl);
 
 #ifdef CONFIG_DUMP_CODE
 void show_code(struct pt_regs *regs);

arch/sh/kernel/dumpstack.c +5 -5

index 959064b90055..d488a47a1f0f 100644
@@ -127,16 +127,16 @@ static const struct stacktrace_ops print_trace_ops = {
 };
 
 void show_trace(struct task_struct *tsk, unsigned long *sp,
-		struct pt_regs *regs)
+		struct pt_regs *regs, const char *loglvl)
 {
 	if (regs && user_mode(regs))
 		return;
 
-	printk("\nCall trace:\n");
+	printk("%s\nCall trace:\n", loglvl);
 
-	unwind_stack(tsk, regs, sp, &print_trace_ops, "");
+	unwind_stack(tsk, regs, sp, &print_trace_ops, (void *)loglvl);
 
-	printk("\n");
+	printk("%s\n", loglvl);
 
 	if (!tsk)
 		tsk = current;

@@ -158,5 +158,5 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
 	stack = (unsigned long)sp;
 	dump_mem("Stack: ", KERN_DEFAULT, stack, THREAD_SIZE +
 		 (unsigned long)task_stack_page(tsk));
-	show_trace(tsk, sp, NULL);
+	show_trace(tsk, sp, NULL, KERN_DEFAULT);
 }

arch/sh/kernel/process_32.c +1 -1

index a094633874c3..456cc8d171f7 100644
@@ -59,7 +59,7 @@ void show_regs(struct pt_regs * regs)
 	printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
 	       regs->mach, regs->macl, regs->gbr, regs->pr);
 
-	show_trace(NULL, (unsigned long *)regs->regs[15], regs);
+	show_trace(NULL, (unsigned long *)regs->regs[15], regs, KERN_DEFAULT);
 	show_code(regs);
 }

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:38 UTC #37 lore raw

PATCH v2 33/50 sh: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Rich Felker <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/sh/kernel/dumpstack.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

arch/sh/kernel/dumpstack.c +9 -3

index d488a47a1f0f..cc51e9d74667 100644
@@ -144,7 +144,8 @@ void show_trace(struct task_struct *tsk, unsigned long *sp,
 	debug_show_held_locks(tsk);
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
+		       const char *loglvl)
 {
 	unsigned long stack;

@@ -156,7 +157,12 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
 		sp = (unsigned long *)tsk->thread.sp;
 
 	stack = (unsigned long)sp;
-	dump_mem("Stack: ", KERN_DEFAULT, stack, THREAD_SIZE +
+	dump_mem("Stack: ", loglvl, stack, THREAD_SIZE +
 		 (unsigned long)task_stack_page(tsk));
-	show_trace(tsk, sp, NULL, KERN_DEFAULT);
+	show_trace(tsk, sp, NULL, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT);
 }

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:39 UTC #38 lore raw

PATCH v2 34/50 sparc: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: "David S. Miller" <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

Acked-by David S. Miller <[email protected]>

---
 arch/sparc/kernel/process_32.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

arch/sparc/kernel/process_32.c +12 -5

index 26cca65e9246..0b07de5618e5 100644
@@ -145,10 +145,12 @@ void show_regs(struct pt_regs *r)
 }
 
 /*
- * The show_stack is an external API which we do not use ourselves.
+ * The show_stack(), show_stack_loglvl() are external APIs which
+ * we do not use ourselves.
  * The oops is printed in die_if_kernel.
  */
-void show_stack(struct task_struct *tsk, unsigned long *_ksp)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *_ksp,
+		       const char *loglvl)
 {
 	unsigned long pc, fp;
 	unsigned long task_base;

@@ -170,11 +172,16 @@ void show_stack(struct task_struct *tsk, unsigned long *_ksp)
 			break;
 		rw = (struct reg_window32 *) fp;
 		pc = rw->ins[7];
-		printk("[%08lx : ", pc);
-		printk("%pS ] ", (void *) pc);
+		printk("%s[%08lx : ", loglvl, pc);
+		printk("%s%pS ] ", loglvl, (void *) pc);
 		fp = rw->ins[6];
 	} while (++count < 16);
-	printk("\n");
+	printk("%s\n", loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT);
 }
 
 /*

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:42 UTC #39 lore raw

PATCH v2 35/50 um/sysrq: Remove needless variable sp

`sp' is a needless excercise here.

Cc Anton Ivanov <[email protected]>

Cc Jeff Dike <[email protected]>

Cc Richard Weinberger <[email protected]>

---
 arch/um/kernel/sysrq.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

arch/um/kernel/sysrq.c +1 -3

index c71b5ef7ea8c..c831a1c2eb94 100644
@@ -27,7 +27,6 @@ static const struct stacktrace_ops stackops = {
 
 void show_stack(struct task_struct *task, unsigned long *stack)
 {
-	unsigned long *sp = stack;
 	struct pt_regs *segv_regs = current->thread.segv_regs;
 	int i;

@@ -38,10 +37,9 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 	}
 
 	if (!stack)
-		sp = get_stack_pointer(task, segv_regs);
+		stack = get_stack_pointer(task, segv_regs);
 
 	pr_info("Stack:\n");
-	stack = sp;
 	for (i = 0; i < 3 * STACKSLOTS_PER_LINE; i++) {
 		if (kstack_end(stack))
 			break;

Signature · 7 lines

2.25.1


_______________________________________________
linux-um mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-um

Dmitry Safonov

author

2020-03-16 14:42 UTC #40 lore raw

PATCH v2 36/50 um: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Anton Ivanov <[email protected]>
Cc: Jeff Dike <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/um/kernel/sysrq.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

arch/um/kernel/sysrq.c +16 -8

index c831a1c2eb94..1b54b6431499 100644
@@ -17,7 +17,9 @@
 
 static void _print_addr(void *data, unsigned long address, int reliable)
 {
-	pr_info(" [<%08lx>] %s%pS\n", address, reliable ? "" : "? ",
+	const char *loglvl = data;
+
+	printk("%s [<%08lx>] %s%pS\n", loglvl, address, reliable ? "" : "? ",
 		(void *)address);
 }

@@ -25,7 +27,8 @@ static const struct stacktrace_ops stackops = {
 	.address = _print_addr
 };
 
-void show_stack(struct task_struct *task, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+		       const char *loglvl)
 {
 	struct pt_regs *segv_regs = current->thread.segv_regs;
 	int i;

@@ -39,17 +42,22 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 	if (!stack)
 		stack = get_stack_pointer(task, segv_regs);
 
-	pr_info("Stack:\n");
+	printk("%sStack:\n", loglvl);
 	for (i = 0; i < 3 * STACKSLOTS_PER_LINE; i++) {
 		if (kstack_end(stack))
 			break;
 		if (i && ((i % STACKSLOTS_PER_LINE) == 0))
-			pr_cont("\n");
+			printk("%s\n", loglvl);
 		pr_cont(" %08lx", *stack++);
 	}
-	pr_cont("\n");
+	printk("%s\n", loglvl);
+
+	printk("%sCall Trace:\n", loglvl);
+	dump_trace(current, &stackops, (void *)loglvl);
+	printk("%s\n", loglvl);
+}
 
-	pr_info("Call Trace:\n");
-	dump_trace(current, &stackops, NULL);
-	pr_info("\n");
+void show_stack(struct task_struct *task, unsigned long *stack)
+{
+	show_stack_loglvl(task, stack, KERN_INFO);
 }

Signature · 7 lines

2.25.1


_______________________________________________
linux-um mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-um

Dmitry Safonov

author

2020-03-16 14:42 UTC #41 lore raw

PATCH v2 37/50 unicore32: Remove unused pmode argument in c_backtrace()

The pmode parameter isn't used in assembly - remove it. Second argument will be reused for printk() log level.

Cc Guan Xuetao <[email protected]>

---
 arch/unicore32/kernel/setup.h |  2 +-
 arch/unicore32/kernel/traps.c | 14 +++++---------
 2 files changed, 6 insertions(+), 10 deletions(-)

arch/unicore32/kernel/setup.h +1 -1

index e40d3603c7e7..03e70e37f472 100644
@@ -29,7 +29,7 @@ extern void kernel_thread_helper(void);
 extern void __init early_signal_init(void);
 
 extern asmlinkage void __backtrace(void);
-extern asmlinkage void c_backtrace(unsigned long fp, int pmode);
+extern asmlinkage void c_backtrace(unsigned long fp);
 
 extern void __show_regs(struct pt_regs *);

arch/unicore32/kernel/traps.c +5 -9

index e24f67283864..3682a4c5d927 100644
@@ -137,7 +137,7 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
 
 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 {
-	unsigned int fp, mode;
+	unsigned int fp;
 	int ok = 1;
 
 	printk(KERN_DEFAULT "Backtrace: ");

@@ -145,16 +145,12 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 	if (!tsk)
 		tsk = current;
 
-	if (regs) {
+	if (regs)
 		fp = regs->UCreg_fp;
-		mode = processor_mode(regs);
-	} else if (tsk != current) {
+	else if (tsk != current)
 		fp = thread_saved_fp(tsk);
-		mode = 0x10;
-	} else {
+	else
 		asm("mov %0, fp" : "=r" (fp) : : "cc");
-		mode = 0x10;
-	}
 
 	if (!fp) {
 		printk("no frame pointer");

@@ -167,7 +163,7 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 	printk("\n");
 
 	if (ok)
-		c_backtrace(fp, mode);
+		c_backtrace(fp);
 }
 
 void show_stack(struct task_struct *tsk, unsigned long *sp)

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:42 UTC #42 lore raw

PATCH v2 38/50 unicore32: Add loglvl to c_backtrace()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Add log level parameter to c_backtrace() as a preparation for introducing show_stack_loglvl()

Cc: Guan Xuetao <[email protected]>
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/unicore32/kernel/setup.h  |  2 +-
 arch/unicore32/kernel/traps.c  |  2 +-
 arch/unicore32/lib/backtrace.S | 24 ++++++++++++++++--------
 3 files changed, 18 insertions(+), 10 deletions(-)

arch/unicore32/kernel/setup.h +1 -1

index 03e70e37f472..967352323185 100644
@@ -29,7 +29,7 @@ extern void kernel_thread_helper(void);
 extern void __init early_signal_init(void);
 
 extern asmlinkage void __backtrace(void);
-extern asmlinkage void c_backtrace(unsigned long fp);
+extern asmlinkage void c_backtrace(unsigned long fp, const char *loglvl);
 
 extern void __show_regs(struct pt_regs *);

arch/unicore32/kernel/traps.c +1 -1

index 3682a4c5d927..2b7d73456865 100644
@@ -163,7 +163,7 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 	printk("\n");
 
 	if (ok)
-		c_backtrace(fp);
+		c_backtrace(fp, KERN_DEFAULT);
 }
 
 void show_stack(struct task_struct *tsk, unsigned long *sp)

arch/unicore32/lib/backtrace.S +16 -8

index f303671e2a4e..6221944b81f3 100644
@@ -16,6 +16,7 @@
 #define sv_fp	v5
 #define sv_pc	v6
 #define offset	v8
+#define loglvl	v9
 
 ENTRY(__backtrace)
 		mov	r0, fp

@@ -27,10 +28,11 @@ ENTRY(c_backtrace)
 ENDPROC(__backtrace)
 ENDPROC(c_backtrace)
 #else
-		stm.w	(v4 - v8, lr), [sp-]	@ Save an extra register
+		stm.w	(v4 - v10, lr), [sp-]	@ Save an extra register
 						@ so we have a location...
 		mov.a	frame, r0		@ if frame pointer is zero
 		beq	no_frame		@ we have no stack frames
+		mov	loglvl, r1
 
 1:		stm.w	(pc), [sp-]		@ calculate offset of PC stored
 		ldw.w	r0, [sp]+, #4		@ by stmfd for this CPU

@@ -95,9 +97,10 @@ for_each_frame:
 		bua	for_each_frame
 
 1006:		adr	r0, .Lbad
-		mov	r1, frame
+		mov	r1, loglvl
+		mov	r2, frame
 		b.l	printk
-no_frame:	ldm.w	(v4 - v8, pc), [sp]+
+no_frame:	ldm.w	(v4 - v10, pc), [sp]+
 ENDPROC(__backtrace)
 ENDPROC(c_backtrace)

@@ -128,8 +131,11 @@ ENDPROC(c_backtrace)
 		add	v7, v7, #1
 		cxor.a	v7, #6
 		cmoveq	v7, #1
-		cmoveq	r1, #'\n'
-		cmovne	r1, #' '
+		bne	201f
+		adr	r0, .Lcr
+		mov	r1, loglvl
+		b.l	printk
+201:
 		ldw.w	r3, [stack]+, #-4
 		mov	r2, reg
 		csub.a	r2, #8

@@ -141,18 +147,20 @@ ENDPROC(c_backtrace)
 		add	r2, r2, #0x10		@ so r2 need add 16
 201:
 		adr	r0, .Lfp
+		mov	r1, loglvl
 		b.l	printk
 2:		sub.a	reg, reg, #1
 		bns	1b
 		cxor.a	v7, #0
 		beq	201f
 		adr	r0, .Lcr
+		mov	r1, loglvl
 		b.l	printk
 201:		ldm.w	(instr, reg, stack, v7, pc), [sp]+
 
-.Lfp:		.asciz	"%cr%d:%08x"
-.Lcr:		.asciz	"\n"
-.Lbad:		.asciz	"Backtrace aborted due to bad frame pointer <%p>\n"
+.Lfp:		.asciz	"%sr%d:%08x "
+.Lcr:		.asciz	"%s\n"
+.Lbad:		.asciz	"%sBacktrace aborted due to bad frame pointer <%p>\n"
 		.align
 .Ldsi:		.word	0x92eec000 >> 14	@ stm.w sp, (... fp, ip, lr, pc)
 		.word	0x92e10000 >> 14	@ stm.w sp, ()

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:42 UTC #43 lore raw

PATCH v2 39/50 unicore32: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

As a nice side-effect - print backtrace in __die() with the same log level as the rest of function.

Cc: Guan Xuetao <[email protected]>
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/unicore32/kernel/traps.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

arch/unicore32/kernel/traps.c +17 ~~-10~~

index 2b7d73456865..8b1335997f50 100644
@@ -135,12 +135,13 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
 	set_fs(fs);
 }
 
-static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
+static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+			   const char *loglvl)
 {
 	unsigned int fp;
 	int ok = 1;
 
-	printk(KERN_DEFAULT "Backtrace: ");
+	printk("%sBacktrace: ", loglvl);
 
 	if (!tsk)
 		tsk = current;

@@ -153,25 +154,31 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 		asm("mov %0, fp" : "=r" (fp) : : "cc");
 
 	if (!fp) {
-		printk("no frame pointer");
+		printk("%sno frame pointer", loglvl);
 		ok = 0;
 	} else if (verify_stack(fp)) {
-		printk("invalid frame pointer 0x%08x", fp);
+		printk("%sinvalid frame pointer 0x%08x", loglvl, fp);
 		ok = 0;
 	} else if (fp < (unsigned long)end_of_stack(tsk))
-		printk("frame pointer underflow");
-	printk("\n");
+		printk("%sframe pointer underflow", loglvl);
+	printk("%s\n", loglvl);
 
 	if (ok)
-		c_backtrace(fp, KERN_DEFAULT);
+		c_backtrace(fp, loglvl);
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
+		       const char *loglvl)
 {
-	dump_backtrace(NULL, tsk);
+	dump_backtrace(NULL, tsk, loglvl);
 	barrier();
 }
 
+void show_stack(struct task_struct *tsk, unsigned long *sp)
+{
+	show_stack_loglvl(tsk, sp, KERN_DEFAULT)
+}
+
 static int __die(const char *str, int err, struct thread_info *thread,
 		struct pt_regs *regs)
 {

@@ -196,7 +203,7 @@ static int __die(const char *str, int err, struct thread_info *thread,
 	if (!user_mode(regs) || in_interrupt()) {
 		dump_mem(KERN_EMERG, "Stack: ", regs->UCreg_sp,
 			 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
-		dump_backtrace(regs, tsk);
+		dump_backtrace(regs, tsk, KERN_EMERG);
 		dump_instr(KERN_EMERG, regs);
 	}

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:42 UTC #44 lore raw

PATCH v2 40/50 x86: Add missing const qualifiers for log_lvl

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Keep log_lvl const show_trace_log_lvl() and printk_stack_address() as the new generic show_stack_loglvl() wants to have a proper const qualifier.

And gcc rightfully produces warnings in case it's not keept:
arch/x86/kernel/dumpstack.c: In function ‘show_stack’:
arch/x86/kernel/dumpstack.c:294:37: warning: passing argument 4 of ‘show_trace_log_lv ’ discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
294 | show_trace_log_lvl(task, NULL, sp, loglvl);
| ^~~~~~
arch/x86/kernel/dumpstack.c:163:32: note: expected ‘char *’ but argument is of type ‘const char *’
163 | unsigned long *stack, char *log_lvl)

      |                          ~~~~~~^~~~~~~

Cc: Borislav Petkov <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/x86/include/asm/stacktrace.h | 2 +-
 arch/x86/kernel/dumpstack.c       | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

arch/x86/include/asm/stacktrace.h +1 -1

index 14db05086bbf..5ae5a68e469d 100644
@@ -87,7 +87,7 @@ get_stack_pointer(struct task_struct *task, struct pt_regs *regs)
 }
 
 void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
-			unsigned long *stack, char *log_lvl);
+			unsigned long *stack, const char *log_lvl);
 
 /* The form of the top of the frame on the stack */
 struct stack_frame {

arch/x86/kernel/dumpstack.c +2 -2

index ae64ec7f752f..b94bc31a1757 100644
@@ -65,7 +65,7 @@ bool in_entry_stack(unsigned long *stack, struct stack_info *info)
 }
 
 static void printk_stack_address(unsigned long address, int reliable,
-				 char *log_lvl)
+				 const char *log_lvl)
 {
 	touch_nmi_watchdog();
 	printk("%s %s%pB\n", log_lvl, reliable ? "" : "? ", (void *)address);

@@ -160,7 +160,7 @@ static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs,
 }
 
 void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
-			unsigned long *stack, char *log_lvl)
+			unsigned long *stack, const char *log_lvl)
 {
 	struct unwind_state state;
 	struct stack_info stack_info = {0};

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:42 UTC #45 lore raw

PATCH v2 41/50 x86: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Borislav Petkov <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/x86/kernel/dumpstack.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

arch/x86/kernel/dumpstack.c +8 -2

index b94bc31a1757..4396f2cfad19 100644
@@ -279,7 +279,8 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 	}
 }
 
-void show_stack(struct task_struct *task, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+		       const char *loglvl)
 {
 	task = task ? : current;

@@ -290,7 +291,12 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 	if (!sp && task == current)
 		sp = get_stack_pointer(current, NULL);
 
-	show_trace_log_lvl(task, NULL, sp, KERN_DEFAULT);
+	show_trace_log_lvl(task, NULL, sp, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT);
 }
 
 void show_stack_regs(struct pt_regs *regs)

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:42 UTC #46 lore raw

PATCH v2 42/50 xtensa: Add loglvl to show_trace()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Add log level argument to show_trace() as a preparation for introducing show_stack_loglvl().

Cc: Chris Zankel <[email protected]>
Cc: Max Filippov <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/xtensa/kernel/traps.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

arch/xtensa/kernel/traps.c +9 -5

index 0976e27b8d5d..c397a02457bc 100644
@@ -479,18 +479,22 @@ void show_regs(struct pt_regs * regs)
 
 static int show_trace_cb(struct stackframe *frame, void *data)
 {
+	const char *loglvl = data;
+
 	if (kernel_text_address(frame->pc))
-		pr_cont(" [<%08lx>] %pB\n", frame->pc, (void *)frame->pc);
+		printk("%s [<%08lx>] %pB\n",
+			loglvl, frame->pc, (void *)frame->pc);
 	return 0;
 }
 
-void show_trace(struct task_struct *task, unsigned long *sp)
+static void show_trace(struct task_struct *task, unsigned long *sp,
+		       const char *loglvl)
 {
 	if (!sp)
 		sp = stack_pointer(task);
 
-	pr_info("Call Trace:\n");
-	walk_stackframe(sp, show_trace_cb, NULL);
+	printk("%sCall Trace:\n", loglvl);
+	walk_stackframe(sp, show_trace_cb, (void *)loglvl);
 }
 
 #define STACK_DUMP_ENTRY_SIZE 4

@@ -511,7 +515,7 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 	print_hex_dump(KERN_INFO, " ", DUMP_PREFIX_NONE,
 		       STACK_DUMP_LINE_SIZE, STACK_DUMP_ENTRY_SIZE,
 		       sp, len, false);
-	show_trace(task, sp);
+	show_trace(task, stack, KERN_INFO);
 }
 
 DEFINE_SPINLOCK(die_lock);

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:42 UTC #47 lore raw

PATCH v2 43/50 xtensa: Add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user).

Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute show_stack().

Cc: Chris Zankel <[email protected]>
Cc: Max Filippov <[email protected]>
Cc: [email protected]
[1]: https://lore.kernel.org/lkml/[email protected]/T/#u

---
 arch/xtensa/kernel/traps.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

arch/xtensa/kernel/traps.c +10 -4

index c397a02457bc..3a50813eeb70 100644
@@ -501,7 +501,8 @@ static void show_trace(struct task_struct *task, unsigned long *sp,
 #define STACK_DUMP_LINE_SIZE 32
 static size_t kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
 
-void show_stack(struct task_struct *task, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+		       const char *loglvl)
 {
 	size_t len;

@@ -511,11 +512,16 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 	len = min((-(size_t)sp) & (THREAD_SIZE - STACK_DUMP_ENTRY_SIZE),
 		  kstack_depth_to_print * STACK_DUMP_ENTRY_SIZE);
 
-	pr_info("Stack:\n");
-	print_hex_dump(KERN_INFO, " ", DUMP_PREFIX_NONE,
+	printk("%sStack:\n", loglvl);
+	print_hex_dump(loglvl, " ", DUMP_PREFIX_NONE,
 		       STACK_DUMP_LINE_SIZE, STACK_DUMP_ENTRY_SIZE,
 		       sp, len, false);
-	show_trace(task, stack, KERN_INFO);
+	show_trace(task, stack, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_INFO);
 }
 
 DEFINE_SPINLOCK(die_lock);

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:43 UTC #48 lore raw

PATCH v2 44/50 sysrq: Use show_stack_loglvl()

Show the stack trace on a CPU with the same log level as "CPU%d" header.

Cc Greg Kroah-Hartman <[email protected]>

Cc Jiri Slaby <[email protected]>

---
 drivers/tty/sysrq.c         | 2 +-
 include/linux/sched/debug.h | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

drivers/tty/sysrq.c +1 -1

index f724962a5906..fe1ffcbda194 100644
@@ -220,7 +220,7 @@ static void showacpu(void *dummy)
 
 	raw_spin_lock_irqsave(&show_lock, flags);
 	pr_info("CPU%d:\n", smp_processor_id());
-	show_stack(NULL, NULL);
+	show_stack_loglvl(NULL, NULL, KERN_INFO);
 	raw_spin_unlock_irqrestore(&show_lock, flags);
 }

include/linux/sched/debug.h +2 -0

index 95fb9e025247..373e4e3faf2a 100644
@@ -31,6 +31,8 @@ extern void show_regs(struct pt_regs *);
  * trace (or NULL if the entire call-chain of the task should be shown).
  */
 extern void show_stack(struct task_struct *task, unsigned long *sp);
+extern void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+			      const char *loglvl);
 
 extern void sched_show_task(struct task_struct *p);

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:43 UTC #49 lore raw

PATCH v2 45/50 x86/amd_gart: Print stacktrace for a leak with KERN_ERR

It's under CONFIG_IOMMU_LEAK option which is enabled by debug config. Likely the backtrace is worth to be seen - so aligning with log level of error message in iommu_full().

Cc Borislav Petkov <[email protected]>

Cc "H. Peter Anvin" <[email protected]>

Cc Ingo Molnar <[email protected]>

Cc Thomas Gleixner <[email protected]>

---
 arch/x86/kernel/amd_gart_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

arch/x86/kernel/amd_gart_64.c +1 -1

index 4e5f50236048..c0fdf594709e 100644
@@ -159,7 +159,7 @@ static void dump_leak(void)
 		return;
 	dump = 1;
 
-	show_stack(NULL, NULL);
+	show_stack_loglvl(NULL, NULL, KERN_ERR);
 	debug_dma_dump_mappings(NULL);
 }
 #endif

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:43 UTC #50 lore raw

PATCH v2 46/50 power: Use show_stack_loglvl()

Aligning with other watchdog messages just before panic - use KERN_EMERG.

Cc Greg Kroah-Hartman <[email protected]>

Cc Len Brown <[email protected]>

Cc Pavel Machek <[email protected]>

Cc "Rafael J. Wysocki" <[email protected]>

---
 drivers/base/power/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/base/power/main.c +1 -1

index 0e99a760aebd..9b8450eab02e 100644
@@ -515,7 +515,7 @@ static void dpm_watchdog_handler(struct timer_list *t)
 	struct dpm_watchdog *wd = from_timer(wd, t, timer);
 
 	dev_emerg(wd->dev, "**** DPM device timeout ****\n");
-	show_stack(wd->tsk, NULL);
+	show_stack_loglvl(wd->tsk, NULL, KERN_EMERG);
 	panic("%s %s: unrecoverable failure\n",
 		dev_driver_string(wd->dev), dev_name(wd->dev));
 }

Signature · 1 line

2.25.1

Rafael J. Wysocki

Acked-by on v2 46/50

2020-03-18 12:54 UTC #51 lore raw

Re: [PATCHv2 46/50] power: Use show_stack_loglvl()

Quoted 9 lines · CET Dmitry Safonov

Aligning with other watchdog messages just before panic - use KERN_EMERG.
Cc Greg Kroah-Hartman <[email protected]>
Cc Len Brown <[email protected]>
Cc Pavel Machek <[email protected]>
Cc "Rafael J. Wysocki" <[email protected]>
Cc [email protected]
Signed-off-by Dmitry Safonov <[email protected]>

Acked-by Rafael J. Wysocki <[email protected]>

or please let me know if I'm expected to take this one.

Quoted 18 lines

---
 drivers/base/power/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/base/power/main.c +1 -1

index 0e99a760aebd..9b8450eab02e 100644
@@ -515,7 +515,7 @@ static void dpm_watchdog_handler(struct timer_list *t)
 	struct dpm_watchdog *wd = from_timer(wd, t, timer);
 
 	dev_emerg(wd->dev, "**** DPM device timeout ****\n");
-	show_stack(wd->tsk, NULL);
+	show_stack_loglvl(wd->tsk, NULL, KERN_EMERG);
 	panic("%s %s: unrecoverable failure\n",
 		dev_driver_string(wd->dev), dev_name(wd->dev));
 }

Dmitry Safonov

author

2020-03-16 14:43 UTC #52 lore raw

PATCH v2 47/50 kdb: Don't play with console_loglevel

Print the stack trace with KERN_EMERG - it should be always visible.

Playing with console_loglevel is a bad idea as there may be more messages printed than wanted. Also the stack trace might be not printed at all if printk() was deferred and console_loglevel was raised back before the trace got flushed.

Unfortunately, after rebasing on commit 2277b492582d ("kdb: Fix stack crawling on 'running' CPUs that aren't the master"), kdb_show_stack() uses now kdb_dump_stack_on_cpu(), which for now won't be converted as it uses dump_stack() instead of show_stack().

Convert for now the branch that uses show_stack() and remove console_loglevel exercise from that case.

Cc Daniel Thompson <[email protected]>

Cc Douglas Anderson <[email protected]>

Cc Jason Wessel <[email protected]>

---
 kernel/debug/kdb/kdb_bt.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

kernel/debug/kdb/kdb_bt.c +8 -7

index 3de0cc780c16..43f5dcd2b9ac 100644
@@ -21,17 +21,18 @@
 
 static void kdb_show_stack(struct task_struct *p, void *addr)
 {
-	int old_lvl = console_loglevel;
-
-	console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
 	kdb_trap_printk++;
 
-	if (!addr && kdb_task_has_cpu(p))
+	if (!addr && kdb_task_has_cpu(p)) {
+		int old_lvl = console_loglevel;
+
+		console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
 		kdb_dump_stack_on_cpu(kdb_process_cpu(p));
-	else
-		show_stack(p, addr);
+		console_loglevel = old_lvl;
+	} else {
+		show_stack_loglvl(p, addr, KERN_EMERG);
+	}
 
-	console_loglevel = old_lvl;
 	kdb_trap_printk--;
 }

Signature · 1 line

2.25.1

Doug Anderson

reviewer Reviewed-by on v2 47/50

2020-03-17 00:07 UTC #53 lore raw

Re: [PATCHv2 47/50] kdb: Don't play with console_loglevel

Hi,

Quoted 16 lines · Dmitry Safonov

Print the stack trace with KERN_EMERG - it should be always visible.
Playing with console_loglevel is a bad idea as there may be more messages printed than wanted. Also the stack trace might be not printed at all if printk() was deferred and console_loglevel was raised back before the trace got flushed.
Unfortunately, after rebasing on commit 2277b492582d ("kdb: Fix stack crawling on 'running' CPUs that aren't the master"), kdb_show_stack() uses now kdb_dump_stack_on_cpu(), which for now won't be converted as it uses dump_stack() instead of show_stack().
Convert for now the branch that uses show_stack() and remove console_loglevel exercise from that case.

Quoted 8 lines

Cc Daniel Thompson <[email protected]>
Cc Douglas Anderson <[email protected]>
Cc Jason Wessel <[email protected]>
Cc [email protected]
Signed-off-by Dmitry Safonov <[email protected]>
---
 kernel/debug/kdb/kdb_bt.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

Presuming that the rest of this series is deemed acceptable by those in charge, this patch looks fine to me:

Reviewed-by Douglas Anderson <[email protected]>

-Doug

Daniel Thompson

Acked-by on v2 47/50

2020-03-17 16:00 UTC #54 lore raw

Re: [PATCHv2 47/50] kdb: Don't play with console_loglevel

Quoted 12 lines · Dmitry Safonov

Print the stack trace with KERN_EMERG - it should be always visible.
Playing with console_loglevel is a bad idea as there may be more messages printed than wanted. Also the stack trace might be not printed at all if printk() was deferred and console_loglevel was raised back before the trace got flushed.
Unfortunately, after rebasing on commit 2277b492582d ("kdb: Fix stack crawling on 'running' CPUs that aren't the master"), kdb_show_stack() uses now kdb_dump_stack_on_cpu(), which for now won't be converted as it uses dump_stack() instead of show_stack().

Quoted 8 lines

Convert for now the branch that uses show_stack() and remove console_loglevel exercise from that case.
Cc Daniel Thompson <[email protected]>
Cc Douglas Anderson <[email protected]>
Cc Jason Wessel <[email protected]>
Cc [email protected]
Signed-off-by Dmitry Safonov <[email protected]>

Acked-by Daniel Thompson <[email protected]>

Quoted 37 lines

---
 kernel/debug/kdb/kdb_bt.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

kernel/debug/kdb/kdb_bt.c +8 -7

index 3de0cc780c16..43f5dcd2b9ac 100644
@@ -21,17 +21,18 @@
 
 static void kdb_show_stack(struct task_struct *p, void *addr)
 {
-	int old_lvl = console_loglevel;
-
-	console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
 	kdb_trap_printk++;
 
-	if (!addr && kdb_task_has_cpu(p))
+	if (!addr && kdb_task_has_cpu(p)) {
+		int old_lvl = console_loglevel;
+
+		console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
 		kdb_dump_stack_on_cpu(kdb_process_cpu(p));
-	else
-		show_stack(p, addr);
+		console_loglevel = old_lvl;
+	} else {
+		show_stack_loglvl(p, addr, KERN_EMERG);
+	}
 
-	console_loglevel = old_lvl;
 	kdb_trap_printk--;
 }

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:43 UTC #55 lore raw

PATCH v2 48/50 sched: Print stack trace with KERN_INFO

Aligning with other messages printed in sched_show_task() - use KERN_INFO to print the backtrace.

Cc Ben Segall <[email protected]>

Cc Dietmar Eggemann <[email protected]>

Cc Ingo Molnar <[email protected]>

Cc Juri Lelli <[email protected]>

Cc Mel Gorman <[email protected]>

Cc Peter Zijlstra <[email protected]>

Cc Steven Rostedt <[email protected]>

Cc Vincent Guittot <[email protected]>

---
 kernel/sched/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

kernel/sched/core.c +1 -1

index 2284deb3a83b..bae2c84077bd 100644
@@ -5948,7 +5948,7 @@ void sched_show_task(struct task_struct *p)
 		(unsigned long)task_thread_info(p)->flags);
 
 	print_worker_info(KERN_INFO, p);
-	show_stack(p, NULL);
+	show_stack_loglvl(p, NULL, KERN_INFO);
 	put_task_stack(p);
 }
 EXPORT_SYMBOL_GPL(sched_show_task);

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:43 UTC #56 lore raw

PATCH v2 49/50 kernel: Use show_stack_loglvl()

Align the last users of show_stack() by KERN_DEFAULT as the surrounding headers/messages.

Cc Ingo Molnar <[email protected]>

Cc Peter Zijlstra <[email protected]>

Cc Will Deacon <[email protected]>

---
 kernel/locking/rtmutex-debug.c | 2 +-
 lib/dump_stack.c               | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

kernel/locking/rtmutex-debug.c +1 -1

index fd4fe1f5b458..5e63d6e8a223 100644
@@ -125,7 +125,7 @@ void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
 
 	printk("\n%s/%d's [blocked] stackdump:\n\n",
 		task->comm, task_pid_nr(task));
-	show_stack(task, NULL);
+	show_stack_loglvl(task, NULL, KERN_DEFAULT);
 	printk("\n%s/%d's [current] stackdump:\n\n",
 		current->comm, task_pid_nr(current));
 	dump_stack();

lib/dump_stack.c +1 -1

index 33ffbf308853..5595e8962cf6 100644
@@ -74,7 +74,7 @@ void show_regs_print_info(const char *log_lvl)
 static void __dump_stack(void)
 {
 	dump_stack_print_info(KERN_DEFAULT);
-	show_stack(NULL, NULL);
+	show_stack_loglvl(NULL, NULL, KERN_DEFAULT);
 }
 
 /**

Signature · 1 line

2.25.1

Dmitry Safonov

author

2020-03-16 14:43 UTC #57 lore raw

PATCH v2 50/50 kernel: Rename show_stack_loglvl() => show_stack()

Now the last users of show_stack() got converted to use an explicit log level, show_stack_loglvl() can drop it's redundant suffix and become once again well known show_stack().