From: Benjamin Segall <bsegall@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Christian Brauner <brauner@kernel.org>,
Eric Biggers <ebiggers@kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: [PATCH v2] epoll: ep_autoremove_wake_function should use list_del_init_careful
Date: Wed, 31 May 2023 16:24:20 -0700 [thread overview]
Message-ID: <xm26bki0ulsr.fsf_-_@google.com> (raw)
In-Reply-To: <20230531152635.e8bb796bee235977c141138c@linux-foundation.org> (Andrew Morton's message of "Wed, 31 May 2023 15:26:35 -0700")
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.
Fixes: a16ceb139610 ("epoll: autoremove wakers even more aggressively")
Signed-off-by: Ben Segall <bsegall@google.com>
Cc: stable@vger.kernel.org
Change-Id: Icca05359250297f091779c9dcf4fefea92ee8c93
---
fs/eventpoll.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 980483455cc09..266d45c7685b4 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1803,11 +1803,15 @@ static struct timespec64 *ep_timeout_to_timespec(struct timespec64 *to, long ms)
static int ep_autoremove_wake_function(struct wait_queue_entry *wq_entry,
unsigned int mode, int sync, void *key)
{
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;
}
/**
* ep_poll - Retrieves ready events, and delivers them to the caller-supplied
--
2.41.0.rc0.172.g3f132b7071-goog
prev parent reply other threads:[~2023-05-31 23:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-30 18:32 [PATCH RESEND] epoll: ep_autoremove_wake_function should use list_del_init_careful Benjamin Segall
2023-05-31 1:57 ` Eric Biggers
2023-05-31 7:53 ` Christian Brauner
2023-05-31 22:15 ` Benjamin Segall
2023-05-31 22:26 ` Andrew Morton
2023-05-31 23:24 ` Benjamin Segall [this message]
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