From 221109ba2127eabd0aa64718543638b58b15df56 Mon Sep 17 00:00:00 2001 From: Jiayuan Chen Date: Sun, 29 Dec 2024 00:44:15 +0530 Subject: [PATCH] bpf: fix recursive lock when verdict program return SK_PASS commit 8ca2a1eeadf09862190b2810697702d803ceef2d upstream. 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 Signed-off-by: Jiayuan Chen Signed-off-by: John Fastabend Acked-by: Martin KaFai Lau Link: https://patch.msgid.link/20241118030910.36230-2-mrpre@163.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin [srish: Apply to stable branch linux-5.10.y] Signed-off-by: Srish Srinivasan Signed-off-by: Sasha Levin --- net/core/skmsg.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/core/skmsg.c b/net/core/skmsg.c index 51792dda1b731..890e16bbc0720 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -940,9 +940,9 @@ static void sk_psock_strp_data_ready(struct sock *sk) if (tls_sw_has_ctx_rx(sk)) { psock->parser.saved_data_ready(sk); } else { - write_lock_bh(&sk->sk_callback_lock); + read_lock_bh(&sk->sk_callback_lock); strp_data_ready(&psock->parser.strp); - write_unlock_bh(&sk->sk_callback_lock); + read_unlock_bh(&sk->sk_callback_lock); } } rcu_read_unlock(); -- 2.47.3