diff mbox series

[net-next] socket: skip checking sk_err for recvmmsg(MSG_ERRQUEUE)

Message ID 20180227232240.145396-1-soheil.kdev@gmail.com
State Accepted, archived
Delegated to: David Miller
Headers show
Series [net-next] socket: skip checking sk_err for recvmmsg(MSG_ERRQUEUE) | expand

Commit Message

Soheil Hassas Yeganeh Feb. 27, 2018, 11:22 p.m. UTC 
From: Soheil Hassas Yeganeh <soheil@google.com>

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 <soheil@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
---
 net/socket.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

Comments

David Miller March 2, 2018, 2:28 a.m. UTC | #1 
From: Soheil Hassas Yeganeh <soheil.kdev@gmail.com>
Date: Tue, 27 Feb 2018 18:22:40 -0500

> From: Soheil Hassas Yeganeh <soheil@google.com>
> 
> 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 <soheil@google.com>
> Reviewed-by: Eric Dumazet <edumazet@google.com>
> Signed-off-by: Willem de Bruijn <willemb@google.com>

Applied, thank you.
diff mbox series

Patch

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;