From: David Miller <davem@davemloft.net>
To: jakub@cloudflare.com
Cc: netdev@vger.kernel.org, john.fastabend@gmail.com,
syzbot+d73682fcf7fee6982fe3@syzkaller.appspotmail.com
Subject: Re: [PATCH net] net, sk_msg: Don't check if sock is locked when tearing down psock
Date: Wed, 22 Jan 2020 20:30:37 +0100 (CET) [thread overview]
Message-ID: <20200122.203037.138201907865382075.davem@davemloft.net> (raw)
In-Reply-To: <20200121123147.706666-1-jakub@cloudflare.com>
From: Jakub Sitnicki <jakub@cloudflare.com>
Date: Tue, 21 Jan 2020 13:31:47 +0100
> As John Fastabend reports [0], psock state tear-down can happen on receive
> path *after* unlocking the socket, if the only other psock user, that is
> sockmap or sockhash, releases its psock reference before tcp_bpf_recvmsg
> does so:
>
> tcp_bpf_recvmsg()
> psock = sk_psock_get(sk) <- refcnt 2
> lock_sock(sk);
> ...
> sock_map_free() <- refcnt 1
> release_sock(sk)
> sk_psock_put() <- refcnt 0
>
> Remove the lockdep check for socket lock in psock tear-down that got
> introduced in 7e81a3530206 ("bpf: Sockmap, ensure sock lock held during
> tear down").
>
> [0] https://lore.kernel.org/netdev/5e25dc995d7d_74082aaee6e465b441@john-XPS-13-9370.notmuch/
>
> Fixes: 7e81a3530206 ("bpf: Sockmap, ensure sock lock held during tear down")
> Reported-by: syzbot+d73682fcf7fee6982fe3@syzkaller.appspotmail.com
> Suggested-by: John Fastabend <john.fastabend@gmail.com>
> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Applied, thank you.
prev parent reply other threads:[~2020-01-22 19:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-21 12:31 [PATCH net] net, sk_msg: Don't check if sock is locked when tearing down psock Jakub Sitnicki
2020-01-22 17:53 ` John Fastabend
2020-01-22 17:59 ` Daniel Borkmann
2020-01-22 19:30 ` David Miller [this message]
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