summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--kernel/locking/mutex-debug.h4
-rw-r--r--kernel/locking/mutex.h10
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)