This is a note to let you know that I've just added the patch titled
x86/unwind/orc: Don't skip the first frame for inactive tasks
to the 5.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-unwind-orc-don-t-skip-the-first-frame-for-inactive-tasks.patch
and it can be found in the queue-5.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f1d9a2abff66aa8156fbc1493abed468db63ea48 Mon Sep 17 00:00:00 2001
From: Miroslav Benes <mbenes@xxxxxxx>
Date: Sat, 25 Apr 2020 05:03:07 -0500
Subject: x86/unwind/orc: Don't skip the first frame for inactive tasks
From: Miroslav Benes <mbenes@xxxxxxx>
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@xxxxxxx>
Signed-off-by: Miroslav Benes <mbenes@xxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Dave Jones <dsj@xxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Link: https://lore.kernel.org/r/7f08db872ab59e807016910acdbe82f744de7065.1587808742.git.jpoimboe@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -651,7 +651,7 @@ 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;
Patches currently in stable-queue which might be from mbenes@xxxxxxx are
queue-5.6/x86-entry-64-fix-unwind-hints-in-kernel-exit-path.patch
queue-5.6/x86-unwind-orc-don-t-skip-the-first-frame-for-inactive-tasks.patch
queue-5.6/x86-unwind-orc-prevent-unwinding-before-orc-initialization.patch
queue-5.6/x86-entry-64-fix-unwind-hints-in-__switch_to_asm.patch
queue-5.6/x86-unwind-orc-fix-error-path-for-bad-orc-entry-type.patch
queue-5.6/x86-entry-64-fix-unwind-hints-in-rewind_stack_do_exit.patch
queue-5.6/x86-unwind-orc-fix-premature-unwind-stoppage-due-to-iret-frames.patch
queue-5.6/x86-entry-64-fix-unwind-hints-in-register-clearing-code.patch
queue-5.6/objtool-fix-stack-offset-tracking-for-indirect-cfas.patch
