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bpf: fix recursive lock when verdict program return SK_PASS

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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: 6648e61322 ("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>
This commit is contained in:
Jiayuan Chen 2024-11-18 11:09:09 +08:00 committed by Jakub Kicinski
parent 21742be898
commit 8ca2a1eead
1 changed files with 2 additions and 2 deletions
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4
net/core/skmsg.c
View File

@ -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();