tcp: Fix listen() regression in 5.15.88.

When we backport dadd0dcaa67d ("net/ulp: prevent ULP without clone op from
entering the LISTEN status"), we have accidentally backported a part of
7a7160edf1bf ("net: Return errno in sk->sk_prot->get_port().") and removed
err = -EADDRINUSE in inet_csk_listen_start().

Thus, listen() no longer returns -EADDRINUSE even if ->get_port() failed
as reported in [0].

We set -EADDRINUSE to err just before ->get_port() to fix the regression.

[0]: https://lore.kernel.org/stable/EF8A45D0-768A-4CD5-9A8A-0FA6E610ABF7@winter.cafe/

Reported-by: Winter <winter@winter.cafe>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index a86140ff093cbf91d699624b3e1e3e869f19b7da..29ec42c1f5d09207d565d42b5f74b00ccd6df3ba 100644 (file)
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -1070,6 +1070,7 @@ int inet_csk_listen_start(struct sock *sk, int backlog)
         * It is OK, because this socket enters to hash table only
         * after validation is complete.
         */
+       err = -EADDRINUSE;
        inet_sk_state_store(sk, TCP_LISTEN);
        if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
                inet->inet_sport = htons(inet->inet_num);