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authorEric Dumazet <edumazet@google.com>2023-01-17 11:01:31 +0000
committerDavid S. Miller <davem@davemloft.net>2023-01-18 14:44:54 +0000
commitb9fb10d131b8c84af9bb14e2078d5c63600c7dea (patch)
treedec2bca723eb44ac91387d8870c22679a59ad06a /net
parentd71ebe8114b4bf622804b810f5e274069060a174 (diff)
l2tp: prevent lockdep issue in l2tp_tunnel_register()
lockdep complains with the following lock/unlock sequence: lock_sock(sk); write_lock_bh(&sk->sk_callback_lock); [1] release_sock(sk); [2] write_unlock_bh(&sk->sk_callback_lock); We need to swap [1] and [2] to fix this issue. Fixes: 0b2c59720e65 ("l2tp: close all race conditions in l2tp_tunnel_register()") Reported-by: syzbot+bbd35b345c7cab0d9a08@syzkaller.appspotmail.com Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/netdev/20230114030137.672706-1-xiyou.wangcong@gmail.com/T/#m1164ff20628671b0f326a24cb106ab3239c70ce3 Cc: Cong Wang <cong.wang@bytedance.com> Cc: Guillaume Nault <gnault@redhat.com> Reviewed-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/l2tp/l2tp_core.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index b6554e32bb12..03608d3ded4b 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1483,10 +1483,8 @@ int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
lock_sock(sk);
write_lock_bh(&sk->sk_callback_lock);
ret = l2tp_validate_socket(sk, net, tunnel->encap);
- if (ret < 0) {
- release_sock(sk);
+ if (ret < 0)
goto err_inval_sock;
- }
rcu_assign_sk_user_data(sk, tunnel);
write_unlock_bh(&sk->sk_callback_lock);
@@ -1523,6 +1521,7 @@ int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
err_inval_sock:
write_unlock_bh(&sk->sk_callback_lock);
+ release_sock(sk);
if (tunnel->fd < 0)
sock_release(sock);