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authorEric Dumazet <edumazet@google.com>2014-03-25 18:42:27 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-04-14 06:42:15 -0700
commitf423fefea41979114d6895a38f112505797aeb48 (patch)
treedbed7028b10ebbcbcc06c7075df483efd2d42c77 /net
parent458b05e1e8b8034e2c9fee5f8170545343e08a3d (diff)
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 94d334781554..75e198d029d2 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1792,8 +1792,11 @@ 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);
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;
}