| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 75/90] x86/unwind/orc: Dont skip the first frame for inactive tasks | Date | Wed, 13 May 2020 11:45:11 +0200 |
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From: Miroslav Benes <mbenes@suse.cz>
commit f1d9a2abff66aa8156fbc1493abed468db63ea48 upstream.
When unwinding an inactive task, the ORC unwinder skips the first frame by default. If both the 'regs' and 'first_frame' parameters of unwind_start() are NULL, 'state->sp' and 'first_frame' are later initialized to the same value for an inactive task. Given there is a "less than or equal to" comparison used at the end of __unwind_start() for skipping stack frames, the first frame is skipped.
Drop the equal part of the comparison and make the behavior equivalent to the frame pointer unwinder.
Fixes: ee9f8fce9964 ("x86/unwind: Add the ORC unwinder") Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Jones <dsj@fb.com> Cc: Jann Horn <jannh@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: https://lore.kernel.org/r/7f08db872ab59e807016910acdbe82f744de7065.1587808742.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/x86/kernel/unwind_orc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -648,7 +648,7 @@ void __unwind_start(struct unwind_state /* Otherwise, skip ahead to the user-specified starting frame: */ while (!unwind_done(state) && (!on_stack(&state->stack_info, first_frame, sizeof(long)) || - state->sp <= (unsigned long)first_frame)) + state->sp < (unsigned long)first_frame)) unwind_next_frame(state); return;
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