af_unix: fix incorrect revert of 'lock_interruptible' in stream receive code

[Willy Tarreau]

As reported by Sultan Qasim, commit 3822b5c ("af_unix: Revert
'lock_interruptible' in stream receive code") was accidently applied
at the wrong place in the backport that appeared in 3.10.95, it
affected unix_dgram_recvmsg() instead of unix_stream_recvmsg() due
to now similar code sections there. The dgram part needs to remain
but the stream part needs to be removed.

Reported-By: Sultan Qasim <sultanqasim@xxxxxxxxx>
Fixes: 3a57e78 (3.10.95)
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
 net/unix/af_unix.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index f934e7b..0061d00 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1934,7 +1934,14 @@ static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
 	if (flags&MSG_OOB)
 		goto out;
 
-	mutex_lock(&u->readlock);
+	err = mutex_lock_interruptible(&u->readlock);
+	if (unlikely(err)) {
+		/* recvmsg() in non blocking mode is supposed to return -EAGAIN
+		 * sk_rcvtimeo is not honored by mutex_lock_interruptible()
+		 */
+		err = noblock ? -EAGAIN : -ERESTARTSYS;
+		goto out;
+	}
 
 	skip = sk_peek_offset(sk, flags);
 
@@ -2083,14 +2090,7 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
 		memset(&tmp_scm, 0, sizeof(tmp_scm));
 	}
 
-	err = mutex_lock_interruptible(&u->readlock);
-	if (unlikely(err)) {
-		/* recvmsg() in non blocking mode is supposed to return -EAGAIN
-		 * sk_rcvtimeo is not honored by mutex_lock_interruptible()
-		 */
-		err = noblock ? -EAGAIN : -ERESTARTSYS;
-		goto out;
-	}
+	mutex_lock(&u->readlock);
 
 	do {
 		int chunk;
-- 
1.7.12.2.21.g234cd45.dirty


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