x86 transition to 4k stacks (2/3)

RFC PATCH New Dave Hansen 1 participant 1 message Oct 15, 2002 Kbuild

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Dave Hansen

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2002-10-15 05:54 UTC #0 lore raw

RFC PATCH 1/1 x86 transition to 4k stacks (2/3)

* stack checking (2/3)
- use gcc's profiling features to check for stack overflows upon entry to functions.
- Warn if the task goes over 4k.
- Panic if the stack gets within 512 bytes of overflowing.

Signature · 2 lines

Dave Hansen
[email protected]

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher. # This patch includes the following deltas:
# ChangeSet 1.851 -> 1.852
# arch/i386/kernel/process.c 1.32 -> 1.33
# arch/i386/Config.help 1.21 -> 1.22
# Makefile 1.320 -> 1.321
# arch/i386/kernel/entry.S 1.38 -> 1.39
# arch/i386/config.in 1.56 -> 1.57
# arch/i386/Makefile 1.21 -> 1.22
# arch/i386/boot/compressed/misc.c 1.9 -> 1.10
# arch/i386/kernel/init_task.c 1.6 -> 1.7
# arch/i386/kernel/i386_ksyms.c 1.34 -> 1.35
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/10/14 haveblue@elm3b96.(none) 1.852
# stack_usage_check-2.5.42+bk-1.patch
# --------------------------------------------
#

Makefile +6 -1

diff -Nru a/Makefile b/Makefile
@@ -156,7 +156,8 @@
 
 CPPFLAGS	:= -D__KERNEL__ -Iinclude
 CFLAGS 		:= $(CPPFLAGS) -Wall -Wstrict-prototypes -Wno-trigraphs -O2 \
-	  	   -fomit-frame-pointer -fno-strict-aliasing -fno-common
+	  	   -fno-strict-aliasing -fno-common
+
 AFLAGS		:= -D__ASSEMBLY__ $(CPPFLAGS)
 
 export	VERSION PATCHLEVEL SUBLEVEL EXTRAVERSION KERNELRELEASE ARCH \

@@ -255,6 +256,10 @@
 
 ifdef CONFIG_MODULES
 export EXPORT_FLAGS := -DEXPORT_SYMTAB
+endif
+
+ifneq ($(CONFIG_FRAME_POINTER),y)
+CFLAGS          += -fomit-frame-pointer
 endif
 
 #

arch/i386/Config.help +4 -0

diff -Nru a/arch/i386/Config.help b/arch/i386/Config.help
@@ -1044,6 +1044,10 @@
   symbolic stack backtraces. This increases the size of the kernel
   somewhat, as all symbols have to be loaded into the kernel image.
 
+CONFIG_X86_STACK_CHECK
+  Say Y here to have the kernel attempt to detect when the per-task
+  kernel stack overflows.  
+
 CONFIG_DEBUG_OBSOLETE
   Say Y here if you want to reduce the chances of the tree compiling,
   and are prepared to dig into driver internals to fix compile errors.

arch/i386/Makefile +4 -0

diff -Nru a/arch/i386/Makefile b/arch/i386/Makefile
@@ -49,6 +49,10 @@
 MACHINE	:= mach-generic
 endif
 
+ifdef CONFIG_X86_STACK_CHECK
+CFLAGS += -p
+endif
+
 HEAD := arch/i386/kernel/head.o arch/i386/kernel/init_task.o
 
 libs-y 					+= arch/i386/lib/

arch/i386/boot/compressed/misc.c +4 -0

diff -Nru a/arch/i386/boot/compressed/misc.c b/arch/i386/boot/compressed/misc.c
@@ -377,3 +377,7 @@
 	if (high_loaded) close_output_buffer_if_we_run_high(mv);
 	return high_loaded;
 }
+
+/* We don't actually check for stack overflows this early. */
+__asm__(".globl mcount ; mcount: ret\n");
+

arch/i386/config.in +5 -0

diff -Nru a/arch/i386/config.in b/arch/i386/config.in
@@ -458,6 +458,11 @@
       bool '  Highmem debugging' CONFIG_DEBUG_HIGHMEM
    fi
    bool '  Load all symbols for debugging/kksymoops' CONFIG_KALLSYMS
+   bool '  Check for stack overflows' CONFIG_X86_STACK_CHECK
+   if [ "$CONFIG_X86_STACK_CHECK" = "y" ]; then
+      define_bool CONFIG_FRAME_POINTER y
+   fi
+
 fi
 
 if [ "$CONFIG_X86_LOCAL_APIC" = "y" ]; then

arch/i386/kernel/entry.S +61 -0

67 lines not on this page · raw message

arch/i386/kernel/i386_ksyms.c +5 -0

diff -Nru a/arch/i386/kernel/i386_ksyms.c b/arch/i386/kernel/i386_ksyms.c
@@ -182,3 +182,8 @@
 EXPORT_SYMBOL(is_sony_vaio_laptop);
 
 EXPORT_SYMBOL(__PAGE_KERNEL);
+
+#ifdef CONFIG_X86_STACK_CHECK
+extern void mcount(void);
+EXPORT_SYMBOL(mcount);
+#endif

arch/i386/kernel/init_task.c +5 -0

diff -Nru a/arch/i386/kernel/init_task.c b/arch/i386/kernel/init_task.c
@@ -13,6 +13,11 @@
 static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
 struct mm_struct init_mm = INIT_MM(init_mm);
 
+#ifdef CONFIG_X86_STACK_CHECK
+union thread_union stack_overflow_stack
+	__attribute__((__section__(".data.init_task")));
+#endif
+
 /*
  * Initial thread structure.
  *

arch/i386/kernel/process.c +15 -1

diff -Nru a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
@@ -156,7 +156,21 @@
 
 __setup("idle=", idle_setup);
 
-void show_regs(struct pt_regs * regs)
+void stack_overflow_warn(void *esp, unsigned long eip)
+{
+	print_symbol("excessive stack use from %s\n", eip);
+	printk("esp: %p\n", esp);
+	show_trace(esp);
+}
+
+void stack_overflow_panic(void *esp, void *eip)
+{
+	printk("stack overflow from %p.  esp: %p\n", eip, esp);
+	show_trace(esp);
+	panic("stack overflow\n");
+}
+
+asmlinkage void show_regs(struct pt_regs * regs)
 {
 	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;