5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Petr Malat oss@malat.biz
[ Upstream commit af295892a7abbf05a3c2ba7abc4d81bb448623d6 ]
Function __sctp_write_space() doesn't set poll key, which leads to ep_poll_callback() waking up all waiters, not only these waiting for the socket being writable. Set the key properly using wake_up_interruptible_poll(), which is preferred over the sync variant, as writers are not woken up before at least half of the queue is available. Also, TCP does the same.
Signed-off-by: Petr Malat oss@malat.biz Acked-by: Xin Long lucien.xin@gmail.com Link: https://patch.msgid.link/20250516081727.1361451-1-oss@malat.biz Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/sctp/socket.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c index d7257eec66b1c..1ac05147dc304 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -8946,7 +8946,8 @@ static void __sctp_write_space(struct sctp_association *asoc) wq = rcu_dereference(sk->sk_wq); if (wq) { if (waitqueue_active(&wq->wait)) - wake_up_interruptible(&wq->wait); + wake_up_interruptible_poll(&wq->wait, EPOLLOUT | + EPOLLWRNORM | EPOLLWRBAND);
/* Note that we try to include the Async I/O support * here by modeling from the current TCP/UDP code.