From 7797dc41417eb0e03f39fc4356f7635bcdef108e Mon Sep 17 00:00:00 2001 From: Soheil Hassas Yeganeh Date: Tue, 27 Feb 2018 18:22:40 -0500 Subject: socket: skip checking sk_err for recvmmsg(MSG_ERRQUEUE) recvmmsg does not call ___sys_recvmsg when sk_err is set. That is fine for normal reads but, for MSG_ERRQUEUE, recvmmsg should always call ___sys_recvmsg regardless of sk->sk_err to be able to clear error queue. Otherwise, users are not able to drain the error queue using recvmmsg. Signed-off-by: Soheil Hassas Yeganeh Reviewed-by: Eric Dumazet Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller --- net/socket.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/net/socket.c b/net/socket.c index 645d32b4872c..d9a1ac233b35 100644 --- a/net/socket.c +++ b/net/socket.c @@ -2289,10 +2289,12 @@ int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen, if (!sock) return err; - err = sock_error(sock->sk); - if (err) { - datagrams = err; - goto out_put; + if (likely(!(flags & MSG_ERRQUEUE))) { + err = sock_error(sock->sk); + if (err) { + datagrams = err; + goto out_put; + } } entry = mmsg; -- cgit v1.2.3-58-ga151