epoll: ep_autoremove_wake_function should use list_del_init_careful

autoremove_wake_function uses list_del_init_careful, so should epoll's more aggressive variant. It only doesn't because it was copied from an older wait.c rather than the most recent. [[email protected]: add comment] Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Fixes: a16ceb1 ("epoll: autoremove wakers even more aggressively") Signed-off-by: Ben Segall <[email protected]> Cc: Al Viro <[email protected]> Cc: Christian Brauner <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]>
chewitt · Jun 12, 2023 · 2192bba · 2192bba
1 parent 4f572f0
commit 2192bba
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
@@ -1805,7 +1805,11 @@ static int ep_autoremove_wake_function(struct wait_queue_entry *wq_entry,
 {
 	int ret = default_wake_function(wq_entry, mode, sync, key);
 
-	list_del_init(&wq_entry->entry);
+	/*
+	 * Pairs with list_empty_careful in ep_poll, and ensures future loop
+	 * iterations see the cause of this wakeup.
+	 */
+	list_del_init_careful(&wq_entry->entry);
 	return ret;
 }