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 5FBADC43441 for ; Sat, 24 Nov 2018 09:46:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2644120874 for ; Sat, 24 Nov 2018 09:46:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="YH1V9J4o" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2644120874 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 S1726123AbeKXUe0 (ORCPT ); Sat, 24 Nov 2018 15:34:26 -0500 Received: from m12-16.163.com ([220.181.12.16]:57191 "EHLO m12-16.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725878AbeKXUe0 (ORCPT ); Sat, 24 Nov 2018 15:34:26 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id; bh=7cISUyBLpwoif6qmk8 OegIZqzP9o3YE8YT9b7KIr0nQ=; b=YH1V9J4oJYWJtcEG9HvIAleze1ReIGVOlM IxkxsD4fk2pRo5X5kkQsPOGSH9vlAFF76r+Evmlw4LGfax5s3Y0is3VX2otppjkk nU537SzCCDJk2tEbCxQa6NWM8WR3cFaFXptOPAhw5C5HIZdaW1n3fUYsF4WqyYFK CoK1S8xco= Received: from bp.localdomain (unknown [106.120.213.96]) by smtp12 (Coremail) with SMTP id EMCowAC3yFNzHflbe0hlBg--.22306S3; Sat, 24 Nov 2018 17:44:23 +0800 (CST) From: Pan Bian To: "Darrick J. Wong" Cc: linux-xfs@vger.kernel.org, Brian Foster , Dave Chinner , Carlos Maiolino , linux-kernel@vger.kernel.org, Pan Bian Subject: [PATCH] xfs: libxfs: move xfs_perag_put late Date: Sat, 24 Nov 2018 17:44:20 +0800 Message-Id: <1543052660-58625-1-git-send-email-bianpan2016@163.com> X-Mailer: git-send-email 2.7.4 X-CM-TRANSID: EMCowAC3yFNzHflbe0hlBg--.22306S3 X-Coremail-Antispam: 1Uf129KBjvdXoW7JFyrZF4UXFyrur43Kw45Jrb_yoWDCFX_Ka 18KFs7A34ktrW7K3W5X395t3WUtF4fG393WayfJFW3K34UGFn3ZwsrXrn0qF13urWaqFZ8 G3yDGFW3KryYvjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUvcSsGvfC2KfnxnUUI43ZEXa7IU89Xo7UUUUU== X-Originating-IP: [106.120.213.96] X-CM-SenderInfo: held01tdqsiiqw6rljoofrz/ Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The function xfs_alloc_get_freelist calls xfs_perag_put to drop the reference. In this case, pag may be released. However, pag->pagf_btreeblks is read and write after the put operation. This may result in a use-after-free bug. This patch moves the put operation late. Signed-off-by: Pan Bian --- fs/xfs/libxfs/xfs_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c index e1c0c0d..4be387d 100644 --- a/fs/xfs/libxfs/xfs_alloc.c +++ b/fs/xfs/libxfs/xfs_alloc.c @@ -2435,7 +2435,6 @@ xfs_alloc_get_freelist( be32_add_cpu(&agf->agf_flcount, -1); xfs_trans_agflist_delta(tp, -1); pag->pagf_flcount--; - xfs_perag_put(pag); logflags = XFS_AGF_FLFIRST | XFS_AGF_FLCOUNT; if (btreeblk) { @@ -2443,6 +2442,7 @@ xfs_alloc_get_freelist( pag->pagf_btreeblks++; logflags |= XFS_AGF_BTREEBLKS; } + xfs_perag_put(pag); xfs_alloc_log_agf(tp, agbp, logflags); *bnop = bno; -- 2.7.4