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x86/dumpstack: Try harder to get a call trace on stack overflow

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If we overflow the stack, print_context_stack() will abort.  Detect
this case and rewind back into the valid part of the stack so that
we can trace it.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/ee1690eb2715ccc5dc187fde94effa4ca0ccbbcd.1468527351.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2016-07-14 13:22:52 -07:00 committed by Ingo Molnar
parent d92fc69cca
commit 9a2e9da3e0
1 changed files with 9 additions and 1 deletions
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10
arch/x86/kernel/dumpstack.c
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@ -87,7 +87,7 @@ static inline int valid_stack_ptr(struct task_struct *task,
else
return 0;
}
return p > t && p < t + THREAD_SIZE - size;
return p >= t && p < t + THREAD_SIZE - size;
}
unsigned long
@ -98,6 +98,14 @@ print_context_stack(struct task_struct *task,
{
struct stack_frame *frame = (struct stack_frame *)bp;
/*
* If we overflowed the stack into a guard page, jump back to the
* bottom of the usable stack.
*/
if ((unsigned long)task_stack_page(task) - (unsigned long)stack <
PAGE_SIZE)
stack = (unsigned long *)task_stack_page(task);
while (valid_stack_ptr(task, stack, sizeof(*stack), end)) {
unsigned long addr;