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authorEric Dumazet <edumazet@google.com>2014-03-25 18:42:27 -0700
committerDavid S. Miller <davem@davemloft.net>2014-03-26 17:05:40 -0400
commitde1443916791d75fdd26becb116898277bb0273f (patch)
tree26fa8bd2f7ea36df46746a2b57e48f3247733d13 /net
parentdc0fe58f356b109c662c6c85562460b0e8be9f5f (diff)
downloadlinux-linaro-stable-de1443916791d75fdd26becb116898277bb0273f.tar.gz
net: unix: non blocking recvmsg() should not return -EINTR
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>
Diffstat (limited to 'net')
-rw-r--r--net/unix/af_unix.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index ce6ec6c2f4de..94404f19f9de 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1787,8 +1787,11 @@ 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;
}
@@ -1913,6 +1916,7 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
struct unix_sock *u = unix_sk(sk);
DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
int copied = 0;
+ int noblock = flags & MSG_DONTWAIT;
int check_creds = 0;
int target;
int err = 0;
@@ -1928,7 +1932,7 @@ 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
@@ -1940,8 +1944,11 @@ 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;
}