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authorCong Wang <cong.wang@bytedance.com>2022-11-02 07:34:17 +0300
committerDaniel Borkmann <daniel@iogearbox.net>2022-11-03 15:51:06 +0300
commit8bbabb3fddcd0f858be69ed5abc9b470a239d6f2 (patch)
tree75c450bd713f4a037f49bb09c5b11db114d7ce52 /net
parenta778f5d46b6287ebe26e24b48f3e8079c2db8ed2 (diff)
downloadlinux-8bbabb3fddcd0f858be69ed5abc9b470a239d6f2.tar.xz
bpf, sock_map: Move cancel_work_sync() out of sock lock
Stanislav reported a lockdep warning, which is caused by the cancel_work_sync() called inside sock_map_close(), as analyzed below by Jakub: psock->work.func = sk_psock_backlog() ACQUIRE psock->work_mutex sk_psock_handle_skb() skb_send_sock() __skb_send_sock() sendpage_unlocked() kernel_sendpage() sock->ops->sendpage = inet_sendpage() sk->sk_prot->sendpage = tcp_sendpage() ACQUIRE sk->sk_lock tcp_sendpage_locked() RELEASE sk->sk_lock RELEASE psock->work_mutex sock_map_close() ACQUIRE sk->sk_lock sk_psock_stop() sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED) cancel_work_sync() __cancel_work_timer() __flush_work() // wait for psock->work to finish RELEASE sk->sk_lock We can move the cancel_work_sync() out of the sock lock protection, but still before saved_close() was called. Fixes: 799aa7f98d53 ("skmsg: Avoid lock_sock() in sk_psock_backlog()") Reported-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Jakub Sitnicki <jakub@cloudflare.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/bpf/20221102043417.279409-1-xiyou.wangcong@gmail.com
Diffstat (limited to 'net')
-rw-r--r--net/core/skmsg.c7
-rw-r--r--net/core/sock_map.c7
2 files changed, 6 insertions, 8 deletions
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 1efdc47a999b..e6b9ced3eda8 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -803,16 +803,13 @@ static void sk_psock_link_destroy(struct sk_psock *psock)
}
}
-void sk_psock_stop(struct sk_psock *psock, bool wait)
+void sk_psock_stop(struct sk_psock *psock)
{
spin_lock_bh(&psock->ingress_lock);
sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
sk_psock_cork_free(psock);
__sk_psock_zap_ingress(psock);
spin_unlock_bh(&psock->ingress_lock);
-
- if (wait)
- cancel_work_sync(&psock->work);
}
static void sk_psock_done_strp(struct sk_psock *psock);
@@ -850,7 +847,7 @@ void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
sk_psock_stop_verdict(sk, psock);
write_unlock_bh(&sk->sk_callback_lock);
- sk_psock_stop(psock, false);
+ sk_psock_stop(psock);
INIT_RCU_WORK(&psock->rwork, sk_psock_destroy);
queue_rcu_work(system_wq, &psock->rwork);
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index a660baedd9e7..81beb16ab1eb 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -1596,7 +1596,7 @@ void sock_map_destroy(struct sock *sk)
saved_destroy = psock->saved_destroy;
sock_map_remove_links(sk, psock);
rcu_read_unlock();
- sk_psock_stop(psock, false);
+ sk_psock_stop(psock);
sk_psock_put(sk, psock);
saved_destroy(sk);
}
@@ -1619,9 +1619,10 @@ void sock_map_close(struct sock *sk, long timeout)
saved_close = psock->saved_close;
sock_map_remove_links(sk, psock);
rcu_read_unlock();
- sk_psock_stop(psock, true);
- sk_psock_put(sk, psock);
+ sk_psock_stop(psock);
release_sock(sk);
+ cancel_work_sync(&psock->work);
+ sk_psock_put(sk, psock);
saved_close(sk, timeout);
}
EXPORT_SYMBOL_GPL(sock_map_close);