The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 2192bba03d80f829233bfa34506b428f71e531e7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2023061737-smartness-mummify-9865@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 2192bba03d80f829233bfa34506b428f71e531e7 Mon Sep 17 00:00:00 2001
From: Benjamin Segall <bsegall(a)google.com>
Date: Tue, 30 May 2023 11:32:28 -0700
Subject: [PATCH] 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.
[bsegall(a)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(a)google.com>
Cc: Al Viro <viro(a)zeniv.linux.org.uk>
Cc: Christian Brauner <brauner(a)kernel.org>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 980483455cc0..266d45c7685b 100644
--- 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;
}