tcp: Fix data-races around sysctl_tcp_migrate_req.

While reading sysctl_tcp_migrate_req, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: f9ac779f88 ("net: Introduce net.ipv4.tcp_migrate_req.")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Kuniyuki Iwashima 2022-07-15 10:17:48 -07:00 committed by David S. Miller
parent f2e383b5bb
commit 4177f54589

View File

@ -387,7 +387,7 @@ void reuseport_stop_listen_sock(struct sock *sk)
prog = rcu_dereference_protected(reuse->prog,
lockdep_is_held(&reuseport_lock));
if (sock_net(sk)->ipv4.sysctl_tcp_migrate_req ||
if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_migrate_req) ||
(prog && prog->expected_attach_type == BPF_SK_REUSEPORT_SELECT_OR_MIGRATE)) {
/* Migration capable, move sk from the listening section
* to the closed section.
@ -545,7 +545,7 @@ struct sock *reuseport_migrate_sock(struct sock *sk,
hash = migrating_sk->sk_hash;
prog = rcu_dereference(reuse->prog);
if (!prog || prog->expected_attach_type != BPF_SK_REUSEPORT_SELECT_OR_MIGRATE) {
if (sock_net(sk)->ipv4.sysctl_tcp_migrate_req)
if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_migrate_req))
goto select_by_hash;
goto failure;
}