From: Benjamin Segall bsegall@google.com
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@google.com: add comment] Link: https://lkml.kernel.org/r/xm26bki0ulsr.fsf_-_@google.com Link: https://lkml.kernel.org/r/xm26pm6hvfer.fsf@google.com Fixes: a16ceb139610 ("epoll: autoremove wakers even more aggressively") Signed-off-by: Ben Segall bsegall@google.com Cc: Al Viro viro@zeniv.linux.org.uk Cc: Christian Brauner brauner@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/eventpoll.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1817,7 +1817,11 @@ 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; }