5.4-stable review patch. If anyone has any objections, please let me know.
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From: Zhongqiu Duan dzq.aishenghu0@gmail.com
[ Upstream commit 3479c7549fb1dfa7a1db4efb7347c7b8ef50de4b ]
If the backlog of listen() is set to zero, sk_acceptq_is_full() allows one connection to be made, but inet_csk_reqsk_queue_is_full() does not. When the net.ipv4.tcp_syncookies is zero, inet_csk_reqsk_queue_is_full() will cause an immediate drop before the sk_acceptq_is_full() check in tcp_conn_request(), resulting in no connection can be made.
This patch tries to keep consistent with 64a146513f8f ("[NET]: Revert incorrect accept queue backlog changes.").
Link: https://lore.kernel.org/netdev/20250102080258.53858-1-kuniyu@amazon.com/ Fixes: ef547f2ac16b ("tcp: remove max_qlen_log") Signed-off-by: Zhongqiu Duan dzq.aishenghu0@gmail.com Reviewed-by: Kuniyuki Iwashima kuniyu@amazon.com Reviewed-by: Jason Xing kerneljasonxing@gmail.com Reviewed-by: Eric Dumazet edumazet@google.com Link: https://patch.msgid.link/20250102171426.915276-1-dzq.aishenghu0@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/inet_connection_sock.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index c81bbfc5f4df..05f07bf60c89 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -285,7 +285,7 @@ static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk) { - return inet_csk_reqsk_queue_len(sk) >= READ_ONCE(sk->sk_max_ack_backlog); + return inet_csk_reqsk_queue_len(sk) > READ_ONCE(sk->sk_max_ack_backlog); }
bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);