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=-8.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT 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 34760C43441 for ; Fri, 23 Nov 2018 10:11:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF58B20820 for ; Fri, 23 Nov 2018 10:11:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="TQlqsjtx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EF58B20820 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=163.com 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 S2409263AbeKWUyz (ORCPT ); Fri, 23 Nov 2018 15:54:55 -0500 Received: from m12-11.163.com ([220.181.12.11]:50115 "EHLO m12-11.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2393883AbeKWUyy (ORCPT ); Fri, 23 Nov 2018 15:54:54 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id; bh=icHIWunFbiRtJzIRcC 0uS1zytXEq3qTYVVTD+GKmUy0=; b=TQlqsjtxeKjYAoQxQEFGvnC4HVZlSNwam5 /9BdzFLK+IxiJiP1AWY4gI64CwRt6sk24sDle5FbatJ25sEWC0fsqXgX19MC9CNm J3hMJmjnr/m1n5RVMxqQ0Skz8bYMx1pOU+AAYZCpC0I4Gi2use9+PZEj4FYV21to I8GiXAKgk= Received: from bp.localdomain (unknown [106.120.213.96]) by smtp7 (Coremail) with SMTP id C8CowACnVJYG0vdbwcgtBg--.58364S3; Fri, 23 Nov 2018 18:10:18 +0800 (CST) From: Pan Bian To: Chris Mason , Josef Bacik , David Sterba Cc: Wang Shilong , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, Pan Bian Subject: [PATCH] btrfs: relocation: set trans to be NULL after free Date: Fri, 23 Nov 2018 18:10:15 +0800 Message-Id: <1542967815-14547-1-git-send-email-bianpan2016@163.com> X-Mailer: git-send-email 2.7.4 X-CM-TRANSID: C8CowACnVJYG0vdbwcgtBg--.58364S3 X-Coremail-Antispam: 1Uf129KBjvdXoWrurWUtr13Zw45AFWUAryUAwb_yoWDWrX_WF 4xtrs2ywn5Xry3CFn0krs5JFZak34FgF1DWwn5t3yakay3ArZ0qr4DXws3Xrs8W398GryY qrZ5Zw18C34fWjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUvcSsGvfC2KfnxnUUI43ZEXa7IUnsXo7UUUUU== X-Originating-IP: [106.120.213.96] X-CM-SenderInfo: held01tdqsiiqw6rljoofrz/1tbiDhMIclXlpkg5VwABsW Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- fs/btrfs/relocation.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 924116f..a3f75b8 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -3959,6 +3959,7 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc) restart: if (update_backref_cache(trans, &rc->backref_cache)) { btrfs_end_transaction(trans); + trans = NULL; continue; } -- 2.7.4