releases/5.4.138/tipc-fix-sleeping-in-tipc-accept-routine.patch

From 0ec576428de8da05dd284808afb8da2c2352ae0c Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Fri, 23 Jul 2021 09:25:34 +0700
Subject: tipc: fix sleeping in tipc accept routine

From: Hoang Le <hoang.h.le@dektech.com.au>

[ Upstream commit d237a7f11719ff9320721be5818352e48071aab6 ]

The release_sock() is blocking function, it would change the state
after sleeping. In order to evaluate the stated condition outside
the socket lock context, switch to use wait_woken() instead.

Fixes: 6398e23cdb1d8 ("tipc: standardize accept routine")
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Hoang Le <hoang.h.le@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/tipc/socket.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index cdade990fe44..a5922ce9109c 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -2501,7 +2501,7 @@ static int tipc_listen(struct socket *sock, int len)
 static int tipc_wait_for_accept(struct socket *sock, long timeo)
 {
 	struct sock *sk = sock->sk;
-	DEFINE_WAIT(wait);
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 	int err;
 
 	/* True wake-one mechanism for incoming connections: only
@@ -2510,12 +2510,12 @@ static int tipc_wait_for_accept(struct socket *sock, long timeo)
 	 * anymore, the common case will execute the loop only once.
 	*/
 	for (;;) {
-		prepare_to_wait_exclusive(sk_sleep(sk), &wait,
-					  TASK_INTERRUPTIBLE);
 		if (timeo && skb_queue_empty(&sk->sk_receive_queue)) {
+			add_wait_queue(sk_sleep(sk), &wait);
 			release_sock(sk);
-			timeo = schedule_timeout(timeo);
+			timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
 			lock_sock(sk);
+			remove_wait_queue(sk_sleep(sk), &wait);
 		}
 		err = 0;
 		if (!skb_queue_empty(&sk->sk_receive_queue))
@@ -2527,7 +2527,6 @@ static int tipc_wait_for_accept(struct socket *sock, long timeo)
 		if (signal_pending(current))
 			break;
 	}
-	finish_wait(sk_sleep(sk), &wait);
 	return err;
 }
 
-- 
2.30.2