tcp/dccp: fix race at listener dismantle phase

Under stress, a close() on a listener can trigger the
WARN_ON(sk->sk_ack_backlog) in inet_csk_listen_stop()

We need to test if listener is still active before queueing
a child in inet_csk_reqsk_queue_add()

Create a common inet_child_forget() helper, and use it
from inet_csk_reqsk_queue_add() and inet_csk_listen_stop()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 7 deletions

diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index e84ea9f2498f..63615709839d 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -268,13 +268,8 @@ struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
 					    struct sock *newsk,
 					    const struct request_sock *req);
 
-static inline void inet_csk_reqsk_queue_add(struct sock *sk,
-					    struct request_sock *req,
-					    struct sock *child)
-{
-	reqsk_queue_add(&inet_csk(sk)->icsk_accept_queue, req, sk, child);
-}
-
+void inet_csk_reqsk_queue_add(struct sock *sk, struct request_sock *req,
+			      struct sock *child);
 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
 				   unsigned long timeout);