diff options
| author | Eric Dumazet <edumazet@google.com> | 2014-03-25 18:42:27 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-04-30 16:23:16 +0100 |
| commit | e7177969baa17560848666cb547b6c05ca86297a (patch) | |
| tree | 585595edfb753885dc188e18c64a902bcc3ff156 | |
| parent | 36672f6303a461e8dee4e1eab5a80bdfb31795f7 (diff) | |
| download | lwn-e7177969baa17560848666cb547b6c05ca86297a.tar.gz lwn-e7177969baa17560848666cb547b6c05ca86297a.zip | |
net: unix: non blocking recvmsg() should not return -EINTR
[ Upstream commit de1443916791d75fdd26becb116898277bb0273f ]
Some applications didn't expect recvmsg() on a non blocking socket
could return -EINTR. This possibility was added as a side effect
of commit b3ca9b02b00704 ("net: fix multithreaded signal handling in
unix recv routines").
To hit this bug, you need to be a bit unlucky, as the u->readlock
mutex is usually held for very small periods.
Fixes: b3ca9b02b00704 ("net: fix multithreaded signal handling in unix recv routines")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | net/unix/af_unix.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 54fc90b2408e..8705ee3b11ef 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1771,8 +1771,11 @@ static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock, goto out; err = mutex_lock_interruptible(&u->readlock); - if (err) { - err = sock_intr_errno(sock_rcvtimeo(sk, noblock)); + 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; } @@ -1887,6 +1890,7 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, struct unix_sock *u = unix_sk(sk); struct sockaddr_un *sunaddr = msg->msg_name; int copied = 0; + int noblock = flags & MSG_DONTWAIT; int check_creds = 0; int target; int err = 0; @@ -1901,7 +1905,7 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, goto out; target = sock_rcvlowat(sk, flags&MSG_WAITALL, size); - timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT); + timeo = sock_rcvtimeo(sk, noblock); /* Lock the socket to prevent queue disordering * while sleeps in memcpy_tomsg @@ -1913,8 +1917,11 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, } err = mutex_lock_interruptible(&u->readlock); - if (err) { - err = sock_intr_errno(timeo); + 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; } |