| Message ID | 20241110082452.40415-2-mrpre@163.com |
|---|---|
| State | New |
| Headers | show |
| Series | bpf: fix recursive lock and add test | expand |
diff --git a/net/core/skmsg.c b/net/core/skmsg.c index b1dcbd3be89e..e90fbab703b2 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -1117,9 +1117,9 @@ static void sk_psock_strp_data_ready(struct sock *sk) if (tls_sw_has_ctx_rx(sk)) { psock->saved_data_ready(sk); } else { - write_lock_bh(&sk->sk_callback_lock); + read_lock_bh(&sk->sk_callback_lock); strp_data_ready(&psock->strp); - write_unlock_bh(&sk->sk_callback_lock); + read_unlock_bh(&sk->sk_callback_lock); } } rcu_read_unlock();
When the stream_verdict program returns SK_PASS, it places the received skb into its own receive queue, but a recursive lock eventually occurs, leading to an operating system deadlock. This issue has been present since v6.9. ''' sk_psock_strp_data_ready write_lock_bh(&sk->sk_callback_lock) strp_data_ready strp_read_sock read_sock -> tcp_read_sock strp_recv cb.rcv_msg -> sk_psock_strp_read # now stream_verdict return SK_PASS without peer sock assign __SK_PASS = sk_psock_map_verd(SK_PASS, NULL) sk_psock_verdict_apply sk_psock_skb_ingress_self sk_psock_skb_ingress_enqueue sk_psock_data_ready read_lock_bh(&sk->sk_callback_lock) <= dead lock ''' This topic has been discussed before, but it has not been fixed. Previous discussion: https://lore.kernel.org/all/6684a5864ec86_403d20898@john.notmuch Fixes: 6648e613226e ("bpf, skmsg: Fix NULL pointer dereference in sk_psock_skb_ingress_enqueue") Reported-by: Vincent Whitchurch <vincent.whitchurch@datadoghq.com> Signed-off-by: Jiayuan Chen <mrpre@163.com> Signed-off-by: John Fastabend <john.fastabend@gmail.com> --- net/core/skmsg.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)