net: mctp: Set SOCK_RCU_FREE

[ Upstream commit 52024cd6ec71a6ca934d0cc12452bd8d49850679 ]

Bind lookup runs under RCU, so ensure that a socket doesn't go away in
the middle of a lookup.

Fixes: 833ef3b91de6 ("mctp: Populate socket implementation")
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Link: https://patch.msgid.link/20250410-mctp-rcu-sock-v1-1-872de9fdc877@codeconstruct.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/mctp/af_mctp.c b/net/mctp/af_mctp.c
index 0ca031866ce1a3d586ef8f76b0dc73d0acb629f8..53b3a294b04241c1179d2c6e3c36c6ddd4a88d3f 100644 (file)
--- a/net/mctp/af_mctp.c
+++ b/net/mctp/af_mctp.c
@@ -253,6 +253,9 @@ static int mctp_sk_hash(struct sock *sk)
 {
        struct net *net = sock_net(sk);
 
+       /* Bind lookup runs under RCU, remain live during that. */
+       sock_set_flag(sk, SOCK_RCU_FREE);
+
        mutex_lock(&net->mctp.bind_lock);
        sk_add_node_rcu(sk, &net->mctp.binds);
        mutex_unlock(&net->mctp.bind_lock);