soreuseport: Clear sk_reuseport_cb before failure in sk_clone().

When sk_clone() fails, sk_destruct() is called for the new socket.

If the parent socket has sk->sk_reuseport_cb, the child will call
reuseport_detach_sock() for the reuseport group.

Let's clear sk->sk_reuseport_cb before any failure path in sk_clone().

Note that this was not a problem before the cited commit because
reuseport_detach_sock() did nothing if the socket was not found in
the reuseport array.

Fixes: 5dc4c4b7d4e8 ("bpf: Introduce BPF_MAP_TYPE_REUSEPORT_SOCKARRAY")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/all/20260709032007.9E4D61F000E9@smtp.kernel.org/
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260709183315.965751-2-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/sock.c b/net/core/sock.c
index 8a59bfaa8096e002afc63fb7d2fbb01f4dd1533f..fc3ff0552d68cfa4882a1ab021ce8958cc36cd73 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2544,6 +2544,8 @@ struct sock *sk_clone(const struct sock *sk, const gfp_t priority,
 
        cgroup_sk_clone(&newsk->sk_cgrp_data);
 
+       RCU_INIT_POINTER(newsk->sk_reuseport_cb, NULL);
+
        rcu_read_lock();
        filter = rcu_dereference(sk->sk_filter);
        if (filter != NULL)
@@ -2566,8 +2568,6 @@ struct sock *sk_clone(const struct sock *sk, const gfp_t priority,
                goto free;
        }
 
-       RCU_INIT_POINTER(newsk->sk_reuseport_cb, NULL);
-
        if (bpf_sk_storage_clone(sk, newsk))
                goto free;