list: Use WRITE_ONCE() when initializing list_head structures
Code that does lockless emptiness testing of non-RCU lists is relying
on INIT_LIST_HEAD() to write the list head's ->next pointer atomically,
particularly when INIT_LIST_HEAD() is invoked from list_del_init().
This commit therefore adds WRITE_ONCE() to this function's pointer stores
that could affect the head's ->next pointer.
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/include/linux/list.h b/include/linux/list.h
index 06c2d88..5356f4d 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -24,7 +24,7 @@
static inline void INIT_LIST_HEAD(struct list_head *list)
{
- list->next = list;
+ WRITE_ONCE(list->next, list);
list->prev = list;
}