x86/unwind: unwind_dump() cleanups

PATCH New Josh Poimboeuf 2 participants 7 messages Apr 18, 2017 – Apr 19, 2017

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x86 x86 stack unwinding

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Josh Poimboeuf

author

2017-04-18 13:13 UTC #0 lore raw

cover x86/unwind: unwind_dump() cleanups

Some minor cleanups related to the unwind_dump() function.

Josh Poimboeuf (3):
x86/unwind: properly zero-pad 32-bit values in unwind_dump() x86/unwind: prepend hex mask value with '0x' in unwind_dump() x86/unwind: remove unused 'sp' argument in unwind_dump()

 arch/x86/kernel/unwind_frame.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

Signature · 1 line

2.7.4

Josh Poimboeuf

author

2017-04-18 13:14 UTC #1 lore raw

PATCH 1/3 x86/unwind: properly zero-pad 32-bit values in unwind_dump()

On x86-32, 32-bit stack values printed by unwind_dump() are confusingly zero-padded to 16 characters (64 bits):

unwind stack type:0 next_sp: (null) mask:a graph_idx:0
f50cdebc: 00000000f50cdec4 (0xf50cdec4)
f50cdec0: 00000000c40489b7 (irq_exit+0x87/0xa0)
...

Instead, base the field width on the size of a long integer so that it looks right on both x86-32 and x86-64.

x86-32:

unwind stack type:1 next_sp: (null) mask:0x2 graph_idx:0
c0ee9d98: c0ee9de0 (init_thread_union+0x1de0/0x2000)
c0ee9d9c: c043fd90 (__save_stack_trace+0x50/0xe0)
...

x86-64:

unwind stack type:1 next_sp: (null) mask:0x2 graph_idx:0
ffffffff81e03b88: ffffffff81e03c10 (init_thread_union+0x3c10/0x4000)
ffffffff81e03b90: ffffffff81048f8e (__save_stack_trace+0x5e/0x100)
...

Reported-by "H. Peter Anvin" <[email protected]>

Signed-off-by Josh Poimboeuf <[email protected]>

---
 arch/x86/kernel/unwind_frame.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

arch/x86/kernel/unwind_frame.c +4 -2

index c461135..3ebe687 100644
@@ -48,11 +48,13 @@ static void unwind_dump(struct unwind_state *state, unsigned long *sp)
 
 		if (zero) {
 			if (!prev_zero)
-				printk_deferred("%p: %016x ...\n", sp, 0);
+				printk_deferred("%p: %0*x ...\n",
+						sp, BITS_PER_LONG/4, 0);
 			continue;
 		}
 
-		printk_deferred("%p: %016lx (%pB)\n", sp, word, (void *)word);
+		printk_deferred("%p: %0*lx (%pB)\n",
+				sp, BITS_PER_LONG/4, word, (void *)word);
 	}
 }

Signature · 1 line

2.7.4

tip-bot for Josh Poimboeuf

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2017-04-19 08:13 UTC #2 lore raw

[tip:x86/asm] x86/unwind: Properly zero-pad 32-bit values in unwind_dump()

x86/unwind: Properly zero-pad 32-bit values in unwind_dump()

Commit-ID:  9b135b234644c9881eee4f5d5683da0f4524722f
Gitweb:     http://git.kernel.org/tip/9b135b234644c9881eee4f5d5683da0f4524722f
Author:     Josh Poimboeuf <[email protected]>
AuthorDate: Tue, 18 Apr 2017 08:12:56 -0500
Committer:  Ingo Molnar <[email protected]>
CommitDate: Wed, 19 Apr 2017 09:59:47 +0200

x86/unwind: Properly zero-pad 32-bit values in unwind_dump()

On x86-32, 32-bit stack values printed by unwind_dump() are confusingly zero-padded to 16 characters (64 bits):

unwind stack type:0 next_sp: (null) mask:a graph_idx:0
f50cdebc: 00000000f50cdec4 (0xf50cdec4)
f50cdec0: 00000000c40489b7 (irq_exit+0x87/0xa0)
...

Instead, base the field width on the size of a long integer so that it looks right on both x86-32 and x86-64.

x86-32:

unwind stack type:1 next_sp: (null) mask:0x2 graph_idx:0
c0ee9d98: c0ee9de0 (init_thread_union+0x1de0/0x2000)
c0ee9d9c: c043fd90 (__save_stack_trace+0x50/0xe0)
...

x86-64:

Reported-by H. Peter Anvin <[email protected]>

Signed-off-by Josh Poimboeuf <[email protected]>

Cc Andy Lutomirski <[email protected]>

Cc Borislav Petkov <[email protected]>

Cc Brian Gerst <[email protected]>

Cc Denys Vlasenko <[email protected]>

Cc Linus Torvalds <[email protected]>

Cc Peter Zijlstra <[email protected]>

Cc Thomas Gleixner <[email protected]>

Link http://lkml.kernel.org/r/36b743812e7eb291d74af4e5067736736622daad.1492520933.git.jpoimboe@redhat.com open here

Signed-off-by Ingo Molnar <[email protected]>

---
 arch/x86/kernel/unwind_frame.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

arch/x86/kernel/unwind_frame.c +4 -2

index c461135..3ebe687 100644
@@ -48,11 +48,13 @@ static void unwind_dump(struct unwind_state *state, unsigned long *sp)
 
 		if (zero) {
 			if (!prev_zero)
-				printk_deferred("%p: %016x ...\n", sp, 0);
+				printk_deferred("%p: %0*x ...\n",
+						sp, BITS_PER_LONG/4, 0);
 			continue;
 		}
 
-		printk_deferred("%p: %016lx (%pB)\n", sp, word, (void *)word);
+		printk_deferred("%p: %0*lx (%pB)\n",
+				sp, BITS_PER_LONG/4, word, (void *)word);
 	}
 }

Josh Poimboeuf

author

2017-04-18 13:14 UTC #3 lore raw

PATCH 2/3 x86/unwind: prepend hex mask value with '0x' in unwind_dump()

In reply to Josh Poimboeuf

In unwind_dump(), the stack mask value is printed in hex, but is confusingly not prepended with '0x'.

Signed-off-by Josh Poimboeuf <[email protected]>

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

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

index 3ebe687..5d26374 100644
@@ -36,7 +36,7 @@ static void unwind_dump(struct unwind_state *state, unsigned long *sp)
 
 	dumped_before = true;
 
-	printk_deferred("unwind stack type:%d next_sp:%p mask:%lx graph_idx:%d\n",
+	printk_deferred("unwind stack type:%d next_sp:%p mask:0x%lx graph_idx:%d\n",
 			state->stack_info.type, state->stack_info.next_sp,
 			state->stack_mask, state->graph_idx);

Signature · 1 line

2.7.4

tip-bot for Josh Poimboeuf

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2017-04-19 08:13 UTC #4 lore raw

[tip:x86/asm] x86/unwind: Prepend hex mask value with '0x' in unwind_dump()

x86/unwind: Prepend hex mask value with '0x' in unwind_dump()

Commit-ID:  4ea3d7410c3597910071182a6bc258c015942887
Gitweb:     http://git.kernel.org/tip/4ea3d7410c3597910071182a6bc258c015942887
Author:     Josh Poimboeuf <[email protected]>
AuthorDate: Tue, 18 Apr 2017 08:12:57 -0500
Committer:  Ingo Molnar <[email protected]>
CommitDate: Wed, 19 Apr 2017 09:59:47 +0200

x86/unwind: Prepend hex mask value with '0x' in unwind_dump()

In unwind_dump(), the stack mask value is printed in hex, but is confusingly not prepended with '0x'.

Signed-off-by Josh Poimboeuf <[email protected]>

Cc Andy Lutomirski <[email protected]>

Cc Borislav Petkov <[email protected]>

Cc Brian Gerst <[email protected]>

Cc Denys Vlasenko <[email protected]>

Cc H. Peter Anvin <[email protected]>

Cc Linus Torvalds <[email protected]>

Cc Peter Zijlstra <[email protected]>

Cc Thomas Gleixner <[email protected]>

Link http://lkml.kernel.org/r/e7fe41be19d73c9f99f53082486473febfe08ffa.1492520933.git.jpoimboe@redhat.com open here

Signed-off-by Ingo Molnar <[email protected]>

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

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

index 3ebe687..5d26374 100644
@@ -36,7 +36,7 @@ static void unwind_dump(struct unwind_state *state, unsigned long *sp)
 
 	dumped_before = true;
 
-	printk_deferred("unwind stack type:%d next_sp:%p mask:%lx graph_idx:%d\n",
+	printk_deferred("unwind stack type:%d next_sp:%p mask:0x%lx graph_idx:%d\n",
 			state->stack_info.type, state->stack_info.next_sp,
 			state->stack_mask, state->graph_idx);

Josh Poimboeuf

author

2017-04-18 13:13 UTC #5 lore raw

PATCH 3/3 x86/unwind: remove unused 'sp' argument in unwind_dump()

In reply to Josh Poimboeuf

The 'sp' argument to unwind_dump() is unused. Remove it.

Signed-off-by Josh Poimboeuf <[email protected]>

---
 arch/x86/kernel/unwind_frame.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

arch/x86/kernel/unwind_frame.c +4 -4

index 5d26374..bda82df 100644
@@ -25,11 +25,11 @@
 	val;						\
 })
 
-static void unwind_dump(struct unwind_state *state, unsigned long *sp)
+static void unwind_dump(struct unwind_state *state)
 {
 	static bool dumped_before = false;
 	bool prev_zero, zero = false;
-	unsigned long word;
+	unsigned long word, *sp;
 
 	if (dumped_before)
 		return;

@@ -287,13 +287,13 @@ bool unwind_next_frame(struct unwind_state *state)
 			"WARNING: kernel stack regs at %p in %s:%d has bad 'bp' value %p\n",
 			state->regs, state->task->comm,
 			state->task->pid, next_bp);
-		unwind_dump(state, (unsigned long *)state->regs);
+		unwind_dump(state);
 	} else {
 		printk_deferred_once(KERN_WARNING
 			"WARNING: kernel stack frame pointer at %p in %s:%d has bad value %p\n",
 			state->bp, state->task->comm,
 			state->task->pid, next_bp);
-		unwind_dump(state, state->bp);
+		unwind_dump(state);
 	}
 the_end:
 	state->stack_info.type = STACK_TYPE_UNKNOWN;

Signature · 1 line

2.7.4

tip-bot for Josh Poimboeuf

merge bot

2017-04-19 08:14 UTC #6 lore raw

[tip:x86/asm] x86/unwind: Remove unused 'sp' parameter in unwind_dump()

x86/unwind: Remove unused 'sp' parameter in unwind_dump()

Commit-ID:  aa4f853461aab5f526a312bf418091a95626632b
Gitweb:     http://git.kernel.org/tip/aa4f853461aab5f526a312bf418091a95626632b
Author:     Josh Poimboeuf <[email protected]>
AuthorDate: Tue, 18 Apr 2017 08:12:58 -0500
Committer:  Ingo Molnar <[email protected]>
CommitDate: Wed, 19 Apr 2017 09:59:47 +0200

x86/unwind: Remove unused 'sp' parameter in unwind_dump()

The 'sp' parameter to unwind_dump() is unused. Remove it.

Signed-off-by Josh Poimboeuf <[email protected]>

Cc Andy Lutomirski <[email protected]>

Cc Borislav Petkov <[email protected]>

Cc Brian Gerst <[email protected]>

Cc Denys Vlasenko <[email protected]>

Cc H. Peter Anvin <[email protected]>

Cc Linus Torvalds <[email protected]>

Cc Peter Zijlstra <[email protected]>

Cc Thomas Gleixner <[email protected]>

Link http://lkml.kernel.org/r/08cb36b004629f6bbcf44c267ae4a609242ebd0b.1492520933.git.jpoimboe@redhat.com open here

Signed-off-by Ingo Molnar <[email protected]>

---
 arch/x86/kernel/unwind_frame.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

arch/x86/kernel/unwind_frame.c +4 -4

index 5d26374..bda82df 100644
@@ -25,11 +25,11 @@
 	val;						\
 })
 
-static void unwind_dump(struct unwind_state *state, unsigned long *sp)
+static void unwind_dump(struct unwind_state *state)
 {
 	static bool dumped_before = false;
 	bool prev_zero, zero = false;
-	unsigned long word;
+	unsigned long word, *sp;
 
 	if (dumped_before)
 		return;

@@ -287,13 +287,13 @@ bad_address:
 			"WARNING: kernel stack regs at %p in %s:%d has bad 'bp' value %p\n",
 			state->regs, state->task->comm,
 			state->task->pid, next_bp);
-		unwind_dump(state, (unsigned long *)state->regs);
+		unwind_dump(state);
 	} else {
 		printk_deferred_once(KERN_WARNING
 			"WARNING: kernel stack frame pointer at %p in %s:%d has bad value %p\n",
 			state->bp, state->task->comm,
 			state->task->pid, next_bp);
-		unwind_dump(state, state->bp);
+		unwind_dump(state);
 	}
 the_end:
 	state->stack_info.type = STACK_TYPE_UNKNOWN;