diff options
| author | Andy Lutomirski <luto@kernel.org> | 2016-07-14 22:22:52 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-07-15 10:26:26 +0200 |
| commit | 9a2e9da3e003112399f2863b7b6b911043c01895 (patch) | |
| tree | 3de10e8eaabd99a08d0c2a10076fc9a455df9661 /arch/x86/kernel/dumpstack.c | |
| parent | x86/mm: Remove kernel_unmap_pages_in_pgd() and efi_cleanup_page_tables() (diff) | |
| download | linux-9a2e9da3e003112399f2863b7b6b911043c01895.tar.xz linux-9a2e9da3e003112399f2863b7b6b911043c01895.zip | |
x86/dumpstack: Try harder to get a call trace on stack overflow
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>
Diffstat (limited to 'arch/x86/kernel/dumpstack.c')
| -rw-r--r-- | arch/x86/kernel/dumpstack.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index ef8017ca5ba9..cc88e25d73e9 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -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; |