This is a note to let you know that I've just added the patch titled
x86/unwind/orc: Prevent unwinding before ORC initialization
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-prevent-unwinding-before-orc-initialization.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 98d0c8ebf77e0ba7c54a9ae05ea588f0e9e3f46e Mon Sep 17 00:00:00 2001
From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Date: Sat, 25 Apr 2020 05:03:08 -0500
Subject: x86/unwind/orc: Prevent unwinding before ORC initialization
From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
commit 98d0c8ebf77e0ba7c54a9ae05ea588f0e9e3f46e upstream.
If the unwinder is called before the ORC data has been initialized,
orc_find() returns NULL, and it tries to fall back to using frame
pointers. This can cause some unexpected warnings during boot.
Move the 'orc_init' check from orc_find() to __unwind_init(), so that it
doesn't even try to unwind from an uninitialized state.
Fixes: ee9f8fce9964 ("x86/unwind: Add the ORC unwinder")
Reviewed-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/069d1499ad606d85532eb32ce39b2441679667d5.1587808742.git.jpoimboe@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/unwind_orc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -142,9 +142,6 @@ static struct orc_entry *orc_find(unsign
{
static struct orc_entry *orc;
- if (!orc_init)
- return NULL;
-
if (ip == 0)
return &null_orc_entry;
@@ -585,6 +582,9 @@ EXPORT_SYMBOL_GPL(unwind_next_frame);
void __unwind_start(struct unwind_state *state, struct task_struct *task,
struct pt_regs *regs, unsigned long *first_frame)
{
+ if (!orc_init)
+ goto done;
+
memset(state, 0, sizeof(*state));
state->task = task;
Patches currently in stable-queue which might be from jpoimboe@xxxxxxxxxx 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
queue-5.6/kvm-vmx-explicitly-clear-rflags.cf-and-rflags.zf-in-vm-exit-rsb-path.patch
