Messages in this thread Patch in this message | | | Date | Wed, 16 Nov 2016 23:19:41 -0800 | From | tip-bot for Josh Poimboeuf <> | Subject | [tip:x86/asm] x86/dumpstack: Handle NULL stack pointer in show_trace_log_lvl() |
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Commit-ID: f4474c9f0bba17857b1a47c8dc89c07a0845c2b2 Gitweb: http://git.kernel.org/tip/f4474c9f0bba17857b1a47c8dc89c07a0845c2b2 Author: Josh Poimboeuf <jpoimboe@redhat.com> AuthorDate: Thu, 17 Nov 2016 00:04:58 -0600 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Thu, 17 Nov 2016 07:48:39 +0100
x86/dumpstack: Handle NULL stack pointer in show_trace_log_lvl()
When show_trace_log_lvl() is called from show_regs(), it completely fails to dump the stack. This bug was introduced when show_stack_log_lvl() was removed with the following commit:
0ee1dd9f5e7e ("x86/dumpstack: Remove raw stack dump")
Previous callers of that function now call show_trace_log_lvl() directly. That resulted in a subtle change, in that the 'stack' argument can now be NULL in certain cases.
A NULL 'stack' pointer means that the stack dump should start from the topmost stack frame unless 'regs' is valid, in which case it should start from 'regs->sp'.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> 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> Fixes: 0ee1dd9f5e7e ("x86/dumpstack: Remove raw stack dump") Link: http://lkml.kernel.org/r/c551842302a9c222d96a14e42e4003f059509f69.1479362652.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/kernel/dumpstack.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index 499aa6f..1e057b0 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -59,6 +59,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, printk("%sCall Trace:\n", log_lvl); unwind_start(&state, task, regs, stack); + stack = stack ? : get_stack_pointer(task, regs); /* * Iterate through the stacks, starting with the current stack pointer.
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