Commit-ID: 99bd28a49b150e4b938313a63b5532d95ba77885 Gitweb: https://git.kernel.org/tip/99bd28a49b150e4b938313a63b5532d95ba77885 Author: Josh Poimboeuf <[email protected]> AuthorDate: Mon, 9 Oct 2017 20:20:04 -0500 Committer: Ingo Molnar <[email protected]> CommitDate: Tue, 10 Oct 2017 12:49:49 +0200
x86/unwind: Align stack pointer in unwinder dump When printing the unwinder dump, the stack pointer could be unaligned, for one of two reasons: - stack corruption; or - GCC created an unaligned stack. There's no way for the unwinder to tell the difference between the two, so we have to assume one or the other. GCC unaligned stacks are very rare, and have only been spotted before GCC 5. Presumably, if we're doing an unwinder stack dump, stack corruption is more likely than a GCC unaligned stack. So always align the stack before starting the dump. Reported-and-tested-by: Tetsuo Handa <[email protected]> Reported-and-tested-by: Fengguang Wu <[email protected]> Signed-off-by: Josh Poimboeuf <[email protected]> Cc: Byungchul Park <[email protected]> Cc: LKP <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: http://lkml.kernel.org/r/2f540c515946ab09ed267e1a1d6421202a0cce08.1507597785.git.jpoim...@redhat.com Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/kernel/unwind_frame.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c index 4949bbc..81aca07 100644 --- a/arch/x86/kernel/unwind_frame.c +++ b/arch/x86/kernel/unwind_frame.c @@ -44,7 +44,8 @@ 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; sp = PTR_ALIGN(stack_info.next_sp, sizeof(long))) { + for (sp = PTR_ALIGN(state->orig_sp, sizeof(long)); sp; + sp = PTR_ALIGN(stack_info.next_sp, sizeof(long))) { if (get_stack_info(sp, state->task, &stack_info, &visit_mask)) break;
