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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 7A900C43381 for ; Fri, 22 Feb 2019 18:25:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4D15B204FD for ; Fri, 22 Feb 2019 18:25:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BHhjE86S" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727397AbfBVSZN (ORCPT ); Fri, 22 Feb 2019 13:25:13 -0500 Received: from mail-pf1-f195.google.com ([209.85.210.195]:37844 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726479AbfBVSZM (ORCPT ); Fri, 22 Feb 2019 13:25:12 -0500 Received: by mail-pf1-f195.google.com with SMTP id s22so1476200pfh.4; Fri, 22 Feb 2019 10:25:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=U/GbfWF0BIqpelcxOHEpWob7GaByLbfgmoKAHpzPzAw=; b=BHhjE86SP2DKz/1Mv4EAScHy7YXQO+9c3rRbZzE5ZWw4L+Ji0o9ENLtwmMq237pqWO RPo33kJxhjxRx6vZBeWk3FXtm3lqqr+NjHMtvnW+SGud0X2MFwwkEGya62FHIAp0iKXC hf/0e0ELIGq18AVktXZs+F9PbtakOWE86IYiMxB6LzR7iP/CNRHGnItbVHU2WjxUUILX OjSiN1DgSPSYQhHEqluLu3/GVnWOP14nfSuQL17a5JTtcY7ZnSYd1paRH8jfcl+WTUAo pP0OIGdb8kWi2nSX8oBVIQrxqyZXEPRm9whm/y4rvdNLFfly/Si+uxK0HxZgQbtBbk7s 3guw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=U/GbfWF0BIqpelcxOHEpWob7GaByLbfgmoKAHpzPzAw=; b=p4LBOrXdQoggDViLA1G5d8QpzRkrr8OjYS5sqZkuQoelBHQgUgGIRIN1X2+G3q3KsM lmEm2LgMh3dkYS7tgAiYr/UIGJ5GA+I0PhwRp1PbvT0Jzzj3ZNJcHZVTcjs9yjsNBCUW jCi1aIiJhaYEM60TXEwMqaB9nWAjQ+E8JsYKWq1Id0mspuPFcdXQQ20+rajVnCQW0q1R ToYK8SMcE8uGgRJ+Wg0L8tdUZfqB+IcKoaohdNQChKtrbS/1MMl3SPjBtIrpJq1VimTw Zw6+IqobRCJ9q7opcU7YIvIfICpYfr349TuCTcFE1JAwC+tseYbKLThzUUY0IB21xygH b2Qw== X-Gm-Message-State: AHQUAuaSHH0o2trZVP2d0qvJ7svk0CNKw1vVhwUNr6n3TM/5CcJNY8zK 7lq9w18DX8TjUfbT2ziaQtQ= X-Google-Smtp-Source: AHgI3IZJSQWPwCj7J/FIfbx4zrK70BuevmDgL2YEFFwV8EOUpVdn2YeWTT8PdvvosWeYKy3a9Jv8qw== X-Received: by 2002:a63:d703:: with SMTP id d3mr5243263pgg.167.1550859911871; Fri, 22 Feb 2019 10:25:11 -0800 (PST) Received: from [192.168.86.235] (c-73-241-150-70.hsd1.ca.comcast.net. [73.241.150.70]) by smtp.gmail.com with ESMTPSA id 10sm4989521pfq.146.2019.02.22.10.25.10 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 22 Feb 2019 10:25:10 -0800 (PST) Subject: Re: [PATCH net] net: socket: set sock->sk to NULL after calling proto_ops::release() To: Eric Biggers , Eric Dumazet Cc: netdev@vger.kernel.org, "David S . Miller" , linux-kernel@vger.kernel.org, Mao Wenan , Cong Wang , Lorenzo Colitti , Tetsuo Handa , Al Viro References: <20190221221356.173485-1-ebiggers@kernel.org> <20190222175743.GA163909@gmail.com> From: Eric Dumazet Message-ID: <0de89a50-6d5c-1d7b-19f5-9a13465bcebd@gmail.com> Date: Fri, 22 Feb 2019 10:25:09 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190222175743.GA163909@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/22/2019 09:57 AM, Eric Biggers wrote: > ->setattr() is called under inode_lock(), which __sock_release() also takes. So > the uses of sock->sk are serialized. See commit 6d8c50dcb029 ("socket: close > race condition between sock_close() and sockfs_setattr()"). Oh right, we added another inode_lock()/inode_unlock() for sock_close() > > The issue now is that if ->setattr() happens *after* __sock_release() (which is > possible if fchownat() gets the reference to the file's 'struct path', then the > file is close()d by another thread, then fchownat() continues), it will see > stale sock->sk because for many socket types it wasn't set to NULL earlier. > > - Eric >