Patch "ax25: Fix segfault after sock connection timeout" 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

ax25: Fix segfault after sock connection timeout

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:
ax25-fix-segfault-after-sock-connection-timeout.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: Basil Gunn <[email protected]>
Date: Sat, 14 Jan 2017 12:18:55 -0800
Subject: ax25: Fix segfault after sock connection timeout

From: Basil Gunn <[email protected]>

[ Upstream commit 8a367e74c0120ef68c8c70d5a025648c96626dff ]

The ax.25 socket connection timed out & the sock struct has been previously taken down ie. sock struct is now a NULL pointer. Checking the sock_flag causes the segfault. Check if the socket struct pointer is NULL before checking sock_flag. This segfault is seen in timed out netrom connections.

Please submit to -stable.

---
 net/ax25/ax25_subr.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -264,7 +264,7 @@ void ax25_disconnect(ax25_cb *ax25, int
 {
 	ax25_clear_queues(ax25);
 
-	if (!sock_flag(ax25->sk, SOCK_DESTROY))
+	if (!ax25->sk || !sock_flag(ax25->sk, SOCK_DESTROY))
 		ax25_stop_heartbeat(ax25);
 	ax25_stop_t1timer(ax25);
 	ax25_stop_t2timer(ax25);

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

queue-4.4/ax25-fix-segfault-after-sock-connection-timeout.patch