This is a note to let you know that I've just added the patch titled
x86,static_call: Fix static-call vs return-thunk
to the 6.5-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-static_call-fix-static-call-vs-return-thunk.patch
and it can be found in the queue-6.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From aee9d30b9744d677509ef790f30f3a24c7841c3d Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Fri, 22 Sep 2023 10:12:25 +0000
Subject: x86,static_call: Fix static-call vs return-thunk
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
commit aee9d30b9744d677509ef790f30f3a24c7841c3d upstream.
Commit
7825451fa4dc ("static_call: Add call depth tracking support")
failed to realize the problem fixed there is not specific to call depth
tracking but applies to all return-thunk uses.
Move the fix to the appropriate place and condition.
Fixes: ee88d363d156 ("x86,static_call: Use alternative RET encoding")
Reported-by: David Kaplan <David.Kaplan@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Reviewed-by: Ingo Molnar <mingo@xxxxxxxxxx>
Tested-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/alternative.c | 3 +++
arch/x86/kernel/callthunks.c | 1 -
2 files changed, 3 insertions(+), 1 deletion(-)
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -720,6 +720,9 @@ void __init_or_module noinline apply_ret
{
s32 *s;
+ if (cpu_feature_enabled(X86_FEATURE_RETHUNK))
+ static_call_force_reinit();
+
for (s = start; s < end; s++) {
void *dest = NULL, *addr = (void *)s + *s;
struct insn insn;
--- a/arch/x86/kernel/callthunks.c
+++ b/arch/x86/kernel/callthunks.c
@@ -272,7 +272,6 @@ void __init callthunks_patch_builtin_cal
pr_info("Setting up call depth tracking\n");
mutex_lock(&text_mutex);
callthunks_setup(&cs, &builtin_coretext);
- static_call_force_reinit();
thunks_initialized = true;
mutex_unlock(&text_mutex);
}
Patches currently in stable-queue which might be from peterz@xxxxxxxxxxxxx are
queue-6.5/kernel-fork-beware-of-__put_task_struct-calling-cont.patch
queue-6.5/x86-ibt-avoid-duplicate-endbr-in-__put_user_nocheck.patch
queue-6.5/x86-static_call-fix-static-call-vs-return-thunk.patch
queue-6.5/x86-ibt-suppress-spurious-endbr.patch
queue-6.5/x86-sched-restore-the-sd_asym_packing-flag-in-the-di.patch
