2 files changed, 10 insertions, 4 deletions

diff --git a/kernel/locking/mutex-debug.h b/kernel/locking/mutex-debug.h
index 0799fd3e4cfa..372e6530180d 100644
--- a/kernel/locking/mutex-debug.h
+++ b/kernel/locking/mutex-debug.h
@@ -29,12 +29,12 @@ extern void debug_mutex_init(struct mutex *lock, const char *name,
 
 static inline void mutex_set_owner(struct mutex *lock)
 {
-        lock->owner = current;
+        WRITE_ONCE(lock->owner, current);
 }
 
 static inline void mutex_clear_owner(struct mutex *lock)
 {
-        lock->owner = NULL;
+        WRITE_ONCE(lock->owner, NULL);
 }
 
 #define spin_lock_mutex(lock, flags)                    \
diff --git a/kernel/locking/mutex.h b/kernel/locking/mutex.h
index 5cda397607f2..12f96199441c 100644
--- a/kernel/locking/mutex.h
+++ b/kernel/locking/mutex.h
@@ -17,14 +17,20 @@
                 __list_del((waiter)->list.prev, (waiter)->list.next)
 
 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
+/*
+ * The mutex owner can get read and written to locklessly.
+ * We should use WRITE_ONCE when writing the owner value to
+ * avoid store tearing, otherwise, a thread could potentially
+ * read a partially written and incomplete owner value.
+ */
 static inline void mutex_set_owner(struct mutex *lock)
 {
-        lock->owner = current;
+        WRITE_ONCE(lock->owner, current);
 }
 
 static inline void mutex_clear_owner(struct mutex *lock)
 {
-        lock->owner = NULL;
+        WRITE_ONCE(lock->owner, NULL);
 }
 #else
 static inline void mutex_set_owner(struct mutex *lock)