| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 084/104] net, sk_msg: Dont check if sock is locked when tearing down psock | Date | Tue, 28 Jan 2020 15:00:45 +0100 |
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From: Jakub Sitnicki <jakub@cloudflare.com>
commit 58c8db929db1c1d785a6f5d8f8692e5dbcc35e84 upstream.
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> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- net/core/skmsg.c | 2 -- 1 file changed, 2 deletions(-)
--- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -594,8 +594,6 @@ EXPORT_SYMBOL_GPL(sk_psock_destroy); void sk_psock_drop(struct sock *sk, struct sk_psock *psock) { - sock_owned_by_me(sk); - sk_psock_cork_free(psock); sk_psock_zap_ingress(psock);
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