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/ (local)
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
---
 net/core/sock.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/sock.c b/net/core/sock.c
index 8a59bfaa8096..fc3ff0552d68 100644
--- 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;
 

-- 
2.55.0.795.g602f6c329a-goog