Messages in this thread Patch in this message | | | From | Andy Lutomirski <> | Subject | [PATCH v3 10/13] x86/dumpstack: Try harder to get a call trace on stack overflow | Date | Mon, 20 Jun 2016 16:43:40 -0700 |
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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> --- arch/x86/kernel/dumpstack.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index d4d085e27d04..9cdf05d768cf 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -89,7 +89,7 @@ static inline int valid_stack_ptr(struct thread_info *tinfo, else return 0; } - return p > t && p < t + THREAD_SIZE - size; + return p >= t && p < t + THREAD_SIZE - size; } unsigned long @@ -100,6 +100,13 @@ print_context_stack(struct thread_info *tinfo, { 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)tinfo - (unsigned long)stack < PAGE_SIZE) + stack = (unsigned long *)tinfo; + while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) { unsigned long addr; -- 2.5.5
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