From: Benjamin Segall <bsegall@xxxxxxxxxx> commit 2192bba03d80f829233bfa34506b428f71e531e7 upstream. 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. [bsegall@xxxxxxxxxx: add comment] Link: https://lkml.kernel.org/r/xm26bki0ulsr.fsf_-_@xxxxxxxxxx Link: https://lkml.kernel.org/r/xm26pm6hvfer.fsf@xxxxxxxxxx Fixes: a16ceb139610 ("epoll: autoremove wakers even more aggressively") Signed-off-by: Ben Segall <bsegall@xxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Christian Brauner <brauner@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/eventpoll.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1760,7 +1760,11 @@ static int ep_autoremove_wake_function(s { 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; }
