[net] tipc: fix sleeping in tipc accept routine

[net] tipc: fix sleeping in tipc accept routine

[Hoang Le]

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>
---
 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 9b0b311c7ec1..2c71828b7e5c 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -2664,7 +2664,7 @@ 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
@@ -2673,12 +2673,12 @@ 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))
@@ -2690,7 +2690,6 @@ 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

Re: [net] tipc: fix sleeping in tipc accept routine

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Fri, 23 Jul 2021 09:25:34 +0700 you wrote:
> 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>
> 
> [...]

Here is the summary with links:
  - [net] tipc: fix sleeping in tipc accept routine
    https://git.kernel.org/netdev/net/c/d237a7f11719

You are awesome, thank you!
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