From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10DB7C2D0DB for ; Wed, 22 Jan 2020 19:30:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CCCCB2064C for ; Wed, 22 Jan 2020 19:30:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726167AbgAVTap (ORCPT ); Wed, 22 Jan 2020 14:30:45 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:50464 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725827AbgAVTao (ORCPT ); Wed, 22 Jan 2020 14:30:44 -0500 Received: from localhost (unknown [62.209.224.147]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 9BDF615A1495A; Wed, 22 Jan 2020 11:30:39 -0800 (PST) Date: Wed, 22 Jan 2020 20:30:37 +0100 (CET) Message-Id: <20200122.203037.138201907865382075.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 From: David Miller In-Reply-To: <20200121123147.706666-1-jakub@cloudflare.com> References: <20200121123147.706666-1-jakub@cloudflare.com> X-Mailer: Mew version 6.8 on Emacs 26.3 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Wed, 22 Jan 2020 11:30:44 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Jakub Sitnicki 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 > Signed-off-by: Jakub Sitnicki Applied, thank you.