This is a note to let you know that I've just added the patch titled
x86/mce: Allow instrumentation during task work queueing
to the 5.10-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-mce-allow-instrumentation-during-task-work-queue.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f5132c876536b269c9ba7b3b2e184b3d032e9f48
Author: Borislav Petkov <bp@xxxxxxx>
Date: Wed Oct 13 09:07:19 2021 +0200
x86/mce: Allow instrumentation during task work queueing
[ Upstream commit 4fbce464db81a42f9a57ee242d6150ec7f996415 ]
Fixes
vmlinux.o: warning: objtool: do_machine_check()+0xdb1: call to queue_task_work() leaves .noinstr.text section
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Link: https://lore.kernel.org/r/20211208111343.8130-6-bp@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 14b34963eb1f7..34fffffaf8730 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1443,6 +1443,14 @@ noinstr void do_machine_check(struct pt_regs *regs)
if (worst != MCE_AR_SEVERITY && !kill_it)
goto out;
+ /*
+ * Enable instrumentation around the external facilities like
+ * task_work_add() (via queue_task_work()), fixup_exception() etc.
+ * For now, that is. Fixing this properly would need a lot more involved
+ * reorganization.
+ */
+ instrumentation_begin();
+
/* Fault was in user mode and we need to take some action */
if ((m.cs & 3) == 3) {
/* If this triggers there is no way to recover. Die hard. */
@@ -1468,6 +1476,9 @@ noinstr void do_machine_check(struct pt_regs *regs)
if (m.kflags & MCE_IN_KERNEL_COPYIN)
queue_task_work(&m, msg, kill_it);
}
+
+ instrumentation_end();
+
out:
mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
}
