diff options
| author | Jiayuan Chen <mrpre@163.com> | 2024-11-18 11:09:09 +0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-11-18 19:39:59 -0800 |
| commit | 8ca2a1eeadf09862190b2810697702d803ceef2d (patch) | |
| tree | 78f1864768407dcf6fadba237f05922b9493a1be | |
| parent | 21742be898fb6d99d4d85e293bd501b6870b503a (diff) | |
| download | lwn-8ca2a1eeadf09862190b2810697702d803ceef2d.tar.gz lwn-8ca2a1eeadf09862190b2810697702d803ceef2d.zip | |
bpf: fix recursive lock when verdict program return SK_PASS
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>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20241118030910.36230-2-mrpre@163.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/core/skmsg.c | 4 |
1 files changed, 2 insertions, 2 deletions
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(); |