Patch "sctp: avoid BUG_ON on sctp_wait_for_sndbuf" has been added to the 4.9-stable tree

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

sctp: avoid BUG_ON on sctp_wait_for_sndbuf

to the 4.9-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:
sctp-avoid-bug_on-on-sctp_wait_for_sndbuf.patch
and it can be found in the queue-4.9 subdirectory.

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

From: Marcelo Ricardo Leitner <[email protected]>
Date: Mon, 6 Feb 2017 18:10:31 -0200
Subject: sctp: avoid BUG_ON on sctp_wait_for_sndbuf

From: Marcelo Ricardo Leitner <[email protected]>

[ Upstream commit 2dcab598484185dea7ec22219c76dcdd59e3cb90 ]

Alexander Popov reported that an application may trigger a BUG_ON in sctp_wait_for_sndbuf if the socket tx buffer is full, a thread is waiting on it to queue more data and meanwhile another thread peels off the association being used by the first thread.

This patch replaces the BUG_ON call with a proper error handling. It will return -EPIPE to the original sendmsg call, similarly to what would have been done if the association wasn't found in the first place.

---
 net/sctp/socket.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -7427,7 +7427,8 @@ static int sctp_wait_for_sndbuf(struct s
 		 */
 		release_sock(sk);
 		current_timeo = schedule_timeout(current_timeo);
-		BUG_ON(sk != asoc->base.sk);
+		if (sk != asoc->base.sk)
+			goto do_error;
 		lock_sock(sk);
 
 		*timeo_p = current_timeo;

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

queue-4.9/sctp-avoid-bug_on-on-sctp_wait_for_sndbuf.patch