Commit-ID: 262fa734a0023a43391f9bd4a4099487b8393f35
Gitweb: http://git.kernel.org/tip/262fa734a0023a43391f9bd4a4099487b8393f35
Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate: Tue, 25 Apr 2017 20:48:52 -0500
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 26 Apr 2017 08:19:05 +0200
x86/unwind: Dump all stacks in unwind_dump()
Currently unwind_dump() dumps only the most recently accessed stack.
But it has a few issues.
In some cases, 'first_sp' can get out of sync with 'stack_info', causing
unwind_dump() to start from the wrong address, flood the printk buffer,
and eventually read a bad address.
In other cases, dumping only the most recently accessed stack doesn't
give enough data to diagnose the error.
Fix both issues by dumping *all* stacks involved in the trace, not just
the last one.
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Fixes: 8b5e99f02264 ("x86/unwind: Dump stack data on warnings")
Link: http://lkml.kernel.org/r/016d6a9810d7d1bfc87ef8c0e6ee041c6744c909.1493171120.git.jpoimboe@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/unwind_frame.c | 34 +++++++++++++++++++++-------------
1 file changed, 21 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index ae0821f..fec70fe 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -30,6 +30,8 @@ static void unwind_dump(struct unwind_state *state)
static bool dumped_before = false;
bool prev_zero, zero = false;
unsigned long word, *sp;
+ struct stack_info stack_info = {0};
+ unsigned long visit_mask = 0;
if (dumped_before)
return;
@@ -40,21 +42,27 @@ static void unwind_dump(struct unwind_state *state)
state->stack_info.type, state->stack_info.next_sp,
state->stack_mask, state->graph_idx);
- for (sp = state->orig_sp; sp < state->stack_info.end; sp++) {
- word = READ_ONCE_NOCHECK(*sp);
+ for (sp = state->orig_sp; sp; sp = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
+ if (get_stack_info(sp, state->task, &stack_info, &visit_mask))
+ break;
- prev_zero = zero;
- zero = word == 0;
+ for (; sp < stack_info.end; sp++) {
- if (zero) {
- if (!prev_zero)
- printk_deferred("%p: %0*x ...\n",
- sp, BITS_PER_LONG/4, 0);
- continue;
- }
+ word = READ_ONCE_NOCHECK(*sp);
+
+ prev_zero = zero;
+ zero = word == 0;
- printk_deferred("%p: %0*lx (%pB)\n",
- sp, BITS_PER_LONG/4, word, (void *)word);
+ if (zero) {
+ if (!prev_zero)
+ printk_deferred("%p: %0*x ...\n",
+ sp, BITS_PER_LONG/4, 0);
+ continue;
+ }
+
+ printk_deferred("%p: %0*lx (%pB)\n",
+ sp, BITS_PER_LONG/4, word, (void *)word);
+ }
}
}
@@ -216,7 +224,7 @@ static bool update_stack_state(struct unwind_state *state,
}
/* Save the original stack pointer for unwind_dump(): */
- if (!state->orig_sp || info->type != prev_type)
+ if (!state->orig_sp)
state->orig_sp = frame;
return true;
--
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