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 <soheil@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/socket.c b/net/socket.c
index 645d32b4..d9a1ac2 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;
