Patch "tcp: correct memory barrier usage in tcp_check_space()" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

tcp: correct memory barrier usage in tcp_check_space()

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
tcp-correct-memory-barrier-usage-in-tcp_check_space.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jason Baron <[email protected]>
Date: Tue, 24 Jan 2017 21:49:41 -0500
Subject: tcp: correct memory barrier usage in tcp_check_space()

From: Jason Baron <[email protected]>

[ Upstream commit 56d806222ace4c3aeae516cd7a855340fb2839d8 ]

sock_reset_flag() maps to __clear_bit() not the atomic version clear_bit(). Thus, we need smp_mb(), smp_mb__after_atomic() is not sufficient.

---
 net/ipv4/tcp_input.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -4942,7 +4942,7 @@ static void tcp_check_space(struct sock
 	if (sock_flag(sk, SOCK_QUEUE_SHRUNK)) {
 		sock_reset_flag(sk, SOCK_QUEUE_SHRUNK);
 		/* pairs with tcp_poll() */
-		smp_mb__after_atomic();
+		smp_mb();
 		if (sk->sk_socket &&
 		    test_bit(SOCK_NOSPACE, &sk->sk_socket->flags))
 			tcp_new_space(sk);

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/tcp-correct-memory-barrier-usage-in-tcp_check_space.patch