Patch "unix/caif: sk_socket can disappear when state is unlocked" has been added to the 4.0-stable tree

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

unix/caif: sk_socket can disappear when state is unlocked

to the 4.0-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:
unix-caif-sk_socket-can-disappear-when-state-is-unlocked.patch
and it can be found in the queue-4.0 subdirectory.

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

From: Mark Salyzyn <[email protected]>
Date: Tue, 26 May 2015 08:22:19 -0700
Subject: unix/caif: sk_socket can disappear when state is unlocked

From: Mark Salyzyn <[email protected]>

[ Upstream commit b48732e4a48d80ed4a14812f0bab09560846514e ]

got a rare NULL pointer dereference in clear_bit

----
v2: switch to sock_flag(sk, SOCK_DEAD) and added net/caif/caif_socket.c
v3: return -ECONNRESET in upstream caller of wait function for SOCK_DEAD

---
 net/caif/caif_socket.c |    8 ++++++++
 net/unix/af_unix.c     |    8 ++++++++
 2 files changed, 16 insertions(+)

@@ -330,6 +330,10 @@ static long caif_stream_data_wait(struct
 		release_sock(sk);
 		timeo = schedule_timeout(timeo);
 		lock_sock(sk);
+
+		if (sock_flag(sk, SOCK_DEAD))
+			break;
+
 		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 	}
 

@@ -374,6 +378,10 @@ static int caif_stream_recvmsg(struct ki
 		struct sk_buff *skb;
 
 		lock_sock(sk);
+		if (sock_flag(sk, SOCK_DEAD)) {
+			err = -ECONNRESET;
+			goto unlock;
+		}
 		skb = skb_dequeue(&sk->sk_receive_queue);
 		caif_check_flow_release(sk);
 

@@ -1887,6 +1887,10 @@ static long unix_stream_data_wait(struct
 		unix_state_unlock(sk);
 		timeo = freezable_schedule_timeout(timeo);
 		unix_state_lock(sk);
+
+		if (sock_flag(sk, SOCK_DEAD))
+			break;
+
 		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 	}
 

@@ -1947,6 +1951,10 @@ static int unix_stream_recvmsg(struct ki
 		struct sk_buff *skb, *last;
 
 		unix_state_lock(sk);
+		if (sock_flag(sk, SOCK_DEAD)) {
+			err = -ECONNRESET;
+			goto unlock;
+		}
 		last = skb = skb_peek(&sk->sk_receive_queue);
 again:
 		if (skb == NULL) {

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

queue-4.0/unix-caif-sk_socket-can-disappear-when-state-is-unlocked.patch