Index: kern_lock.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_lock.c,v
diff -u -p -r1.75 kern_lock.c
--- kern_lock.c	3 Jul 2024 01:36:50 -0000	1.75
+++ kern_lock.c	17 Oct 2024 03:38:09 -0000
@@ -326,24 +377,31 @@ mtx_enter_try(struct mutex *mtx)
 void
 mtx_leave(struct mutex *mtx)
 {
+	struct cpu_info *ci = curcpu();
+	struct cpu_info *owner;
 	int s;
 
 	/* Avoid deadlocks after panic or in DDB */
 	if (panicstr || db_active)
 		return;
 
-	MUTEX_ASSERT_LOCKED(mtx);
 	WITNESS_UNLOCK(MUTEX_LOCK_OBJECT(mtx), LOP_EXCLUSIVE);
 
 #ifdef DIAGNOSTIC
-	curcpu()->ci_mutex_level--;
+	ci->ci_mutex_level--;
 #endif
 
 	s = mtx->mtx_oldipl;
 #ifdef MULTIPROCESSOR
-	membar_exit();
-#endif
+	membar_exit_before_atomic();
+	owner = atomic_cas_ptr(&mtx->mtx_owner, ci, NULL);
+#else
+	owner = mtx->mtx_owner;
 	mtx->mtx_owner = NULL;
+#endif
+	if (__predict_false(owner != ci))
+		panic("mtx %p: not held in unlock", mtx);
+
 	if (mtx->mtx_wantipl != IPL_NONE)
 		splx(s);
 }