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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 6C894C43441 for ; Fri, 23 Nov 2018 12:47:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D55B20672 for ; Fri, 23 Nov 2018 12:47:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3D55B20672 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2409943AbeKWXbK (ORCPT ); Fri, 23 Nov 2018 18:31:10 -0500 Received: from mx2.suse.de ([195.135.220.15]:38614 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2394756AbeKWXbJ (ORCPT ); Fri, 23 Nov 2018 18:31:09 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id AFDB7AEFA; Fri, 23 Nov 2018 12:47:04 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id BCF29DA858; Fri, 23 Nov 2018 13:46:49 +0100 (CET) Date: Fri, 23 Nov 2018 13:46:49 +0100 From: David Sterba To: Pan Bian Cc: Chris Mason , Josef Bacik , David Sterba , Wang Shilong , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] btrfs: relocation: set trans to be NULL after free Message-ID: <20181123124648.GB2842@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Pan Bian , Chris Mason , Josef Bacik , David Sterba , Wang Shilong , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org References: <1542967815-14547-1-git-send-email-bianpan2016@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1542967815-14547-1-git-send-email-bianpan2016@163.com> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 23, 2018 at 06:10:15PM +0800, Pan Bian wrote: > The function relocate_block_group calls btrfs_end_transaction to release > trans when update_backref_cache returns 1, and then continues the loop > body. If btrfs_block_rsv_refill fails this time, it will jump out the > loop and the freed trans will be accessed. This may result in a > use-after-free bug. The patch assigns NULL to trans after trans is > released so that it will not be accessed. > > Fixes: 0647bf564f1("Btrfs: improve forever loop when doing balance > relocation") > > Signed-off-by: Pan Bian Good catch, thanks. Reviewed-by: David Sterba