kernel/include/net/inet_connection_sock.h, branch master

tcp: fix potential race in tcp_v6_syn_recv_sock()

2026-02-19T22:02:19Z

Code in tcp_v6_syn_recv_sock() after the call to tcp_v4_syn_recv_sock() is done too late. After tcp_v4_syn_recv_sock(), the child socket is already visible from TCP ehash table and other cpus might use it. Since newinet->pinet6 is still pointing to the listener ipv6_pinfo bad things can happen as syzbot found. Move the problematic code in tcp_v6_mapped_child_init() and call this new helper from tcp_v4_syn_recv_sock() before the ehash insertion. This allows the removal of one tcp_sync_mss(), since tcp_v4_syn_recv_sock() will call it with the correct context. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+937b5bbb6a815b3e5d0b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/69949275.050a0220.2eeac1.0145.GAE@google.com/ Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260217161205.2079883-1-edumazet@google.com Signed-off-by: Jakub Kicinski

tcp: remove icsk->icsk_retransmit_timer

2025-11-26T03:28:29Z

Now sk->sk_timer is no longer used by TCP keepalive, we can use its storage for TCP and MPTCP retransmit timers for better cache locality. Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20251124175013.1473655-5-edumazet@google.com Signed-off-by: Jakub Kicinski

tcp: introduce icsk->icsk_keepalive_timer

2025-11-26T03:28:29Z

sk->sk_timer has been used for TCP keepalives. Keepalive timers are not in fast path, we want to use sk->sk_timer storage for retransmit timers, for better cache locality. Create icsk->icsk_keepalive_timer and change keepalive code to no longer use sk->sk_timer. Added space is reclaimed in the following patch. This includes changes to MPTCP, which was also using sk_timer. Alias icsk->mptcp_tout_timer and icsk->icsk_keepalive_timer for inet_sk_diag_fill() sake. Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20251124175013.1473655-4-edumazet@google.com Signed-off-by: Jakub Kicinski

tcp: rename icsk_timeout() to tcp_timeout_expires()

2025-11-26T03:28:28Z

In preparation of sk->tcp_timeout_timer introduction, rename icsk_timeout() helper and change its argument to plain 'const struct sock *sk'. Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20251124175013.1473655-2-edumazet@google.com Signed-off-by: Jakub Kicinski

tcp: Remove timeout arg from reqsk_timeout().

2025-11-08T02:05:26Z

reqsk_timeout() is always called with @timeout being TCP_RTO_MAX. Let's remove the arg. As a prep for the next patch, reqsk_timeout() is moved to tcp.h and renamed to tcp_reqsk_timeout(). Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20251106003357.273403-5-kuniyu@google.com Signed-off-by: Jakub Kicinski

tcp: Remove timeout arg from reqsk_queue_hash_req().

2025-11-08T02:05:25Z

inet_csk_reqsk_queue_hash_add() is no longer shared by DCCP. We do not need to pass req->timeout down to reqsk_queue_hash_req(). Let's move tcp_timeout_init() from tcp_conn_request() to reqsk_queue_hash_req(). Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20251106003357.273403-3-kuniyu@google.com Signed-off-by: Jakub Kicinski

tcp: Update bind bucket state on port release

2025-09-23T08:12:15Z

Today, once an inet_bind_bucket enters a state where fastreuse >= 0 or fastreuseport >= 0 after a socket is explicitly bound to a port, it remains in that state until all sockets are removed and the bucket is destroyed. In this state, the bucket is skipped during ephemeral port selection in connect(). For applications using a reduced ephemeral port range (IP_LOCAL_PORT_RANGE socket option), this can cause faster port exhaustion since blocked buckets are excluded from reuse. The reason the bucket state isn't updated on port release is unclear. Possibly a performance trade-off to avoid scanning bucket owners, or just an oversight. Fix it by recalculating the bucket state when a socket releases a port. To limit overhead, each inet_bind2_bucket stores its own (fastreuse, fastreuseport) state. On port release, only the relevant port-addr bucket is scanned, and the overall state is derived from these. Signed-off-by: Jakub Sitnicki Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250917-update-bind-bucket-state-on-unhash-v5-1-57168b661b47@cloudflare.com Signed-off-by: Paolo Abeni

tcp: Remove sk->sk_prot->orphan_count.

2025-09-01T19:52:09Z

TCP tracks the number of orphaned (SOCK_DEAD but not yet destructed) sockets in tcp_orphan_count. In some code that was shared with DCCP, tcp_orphan_count is referenced via sk->sk_prot->orphan_count. Let's reference tcp_orphan_count directly. inet_csk_prepare_for_destroy_sock() is moved to inet_connection_sock.c due to header dependency. Signed-off-by: Kuniyuki Iwashima Reviewed-by: Jason Xing Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250829215641.711664-1-kuniyu@google.com Signed-off-by: Jakub Kicinski

tcp/dccp: remove icsk->icsk_ack.timeout

2025-03-25T17:34:33Z

icsk->icsk_ack.timeout can be replaced by icsk->csk_delack_timer.expires This saves 8 bytes in TCP/DCCP sockets and helps for better cache locality. Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250324203607.703850-3-edumazet@google.com Signed-off-by: Jakub Kicinski

tcp/dccp: remove icsk->icsk_timeout

2025-03-25T17:34:33Z

icsk->icsk_timeout can be replaced by icsk->icsk_retransmit_timer.expires This saves 8 bytes in TCP/DCCP sockets and helps for better cache locality. Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250324203607.703850-2-edumazet@google.com Signed-off-by: Jakub Kicinski