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=-1.0 required=3.0 tests=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 B605BC43444 for ; Wed, 2 Jan 2019 09:34:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8DCBD218A4 for ; Wed, 2 Jan 2019 09:34:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728924AbfABJe4 (ORCPT ); Wed, 2 Jan 2019 04:34:56 -0500 Received: from mx1.redhat.com ([209.132.183.28]:35000 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726782AbfABJez (ORCPT ); Wed, 2 Jan 2019 04:34:55 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7376DC059B8C; Wed, 2 Jan 2019 09:34:55 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-244.rdu2.redhat.com [10.10.120.244]) by smtp.corp.redhat.com (Postfix) with ESMTP id EB9E46013B; Wed, 2 Jan 2019 09:34:53 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20181226135618.12784-1-baijiaju1990@gmail.com> References: <20181226135618.12784-1-baijiaju1990@gmail.com> To: Jia-Ju Bai Cc: dhowells@redhat.com, benh@kernel.crashing.org, joel@jms.id.au, eajames@linux.vnet.ibm.com, andrew@aj.id.au, linux-kernel@vger.kernel.org Subject: Re: [PATCH] fsi:fsi-sbefifo: Fix possible concurrency use-after-free bugs in sbefifo_user_release MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <26863.1546421693.1@warthog.procyon.org.uk> Date: Wed, 02 Jan 2019 09:34:53 +0000 Message-ID: <26864.1546421693@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Wed, 02 Jan 2019 09:34:55 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jia-Ju Bai wrote: > + mutex_lock(&user->file_lock); > sbefifo_release_command(user); > free_page((unsigned long)user->cmd_page); > + mutex_unlock(&user->file_lock); It shouldn't be necessary to do the free_page() call inside the locked section. David