[PATCH 3.10 01/53] af_unix: fix incorrect revert of lock_interruptible in stream receive code

From: Greg Kroah-Hartman
Date: Wed Jan 27 2016 - 15:05:43 EST


3.10-stable review patch. If anyone has any objections, please let me know.

------------------

From: Willy Tarreau <w@xxxxxx>

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(-)

--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1934,7 +1934,14 @@ static int unix_dgram_recvmsg(struct kio
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 ki
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;