From: Borislav Petkov <bp@suse.de>
Date: Wed, 13 Oct 2021 09:07:19 +0200
Subject: x86/mce: Allow instrumentation during task work queueing
Git-commit: 4fbce464db81a42f9a57ee242d6150ec7f996415
Patch-mainline: 5.17-rc1
References: git-fixes

Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0xdb1: call to queue_task_work() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-6-bp@alien8.de
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 arch/x86/kernel/cpu/mce/core.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1436,6 +1436,14 @@ noinstr void do_machine_check(struct pt_
 	if (worst != MCE_AR_SEVERITY && !kill_current_task)
 		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. */
@@ -1461,6 +1469,9 @@ noinstr void do_machine_check(struct pt_
 		if (m.kflags & MCE_IN_KERNEL_COPYIN)
 			queue_task_work(&m, msg, kill_current_task);
 	}
+
+	instrumentation_end();
+
 out:
 	mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
 }