[{"id":1763510,"web_url":"http://patchwork.ozlabs.org/comment/1763510/","msgid":"","list_archive_url":null,"date":"2017-09-05T17:07:48","subject":"Re: [PATCH][ext4-next] ext4: fix null pointer dereference on sbi","submitter":{"id":347,"url":"http://patchwork.ozlabs.org/api/people/347/","name":"Dan Williams","email":"dan.j.williams@intel.com"},"content":"On Tue, Sep 5, 2017 at 9:51 AM, Colin King wrote:\n> From: Colin Ian King \n>\n> In the case of a kzalloc failure when allocating sbi we end up\n> with a null pointer dereference on sbi when assigning sbi->s_daxdev.\n> Fix this by moving the assignment of sbi->s_daxdev to after the\n> null pointer check of sbi.\n>\n> Detected by CoverityScan CID#1455379 (\"Dereference before null check\")\n>\n> Fixes: 5e405595e5bf (\"ext4: perform dax_device lookup at mount\")\n> Signed-off-by: Colin Ian King \n> ---\n> fs/ext4/super.c | 2 +-\n> 1 file changed, 1 insertion(+), 1 deletion(-)\n>\n> diff --git a/fs/ext4/super.c b/fs/ext4/super.c\n> index 0e63fcd12c5b..71b9a667e1bc 100644\n> --- a/fs/ext4/super.c\n> +++ b/fs/ext4/super.c\n> @@ -3422,10 +3422,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)\n> unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;\n> ext4_group_t first_not_zeroed;\n>\n> - sbi->s_daxdev = dax_dev;\n> if ((data && !orig_data) || !sbi)\n> goto out_free_base;\n>\n> + sbi->s_daxdev = dax_dev;\n> sbi->s_blockgroup_lock =\n> kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);\n> if (!sbi->s_blockgroup_lock)\n\nThanks, this looks obviously correct to me. I'll append to the branch\nwith 5e405595e5bf.","headers":{"Return-Path":"","X-Original-To":"patchwork-incoming@ozlabs.org","Delivered-To":"patchwork-incoming@ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; helo=vger.kernel.org;\n\tenvelope-from=linux-ext4-owner@vger.kernel.org;\n\treceiver=)","ozlabs.org; dkim=pass (2048-bit key;\n\tunprotected) header.d=intel-com.20150623.gappssmtp.com\n\theader.i=@intel-com.20150623.gappssmtp.com\n\theader.b=\"KHvW5Ybw\"; dkim-atps=neutral"],"Received":["from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xmtSw20Fnz9t16\n\tfor ;\n\tWed, 6 Sep 2017 03:08:00 +1000 (AEST)","(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1752218AbdIERHv (ORCPT );\n\tTue, 5 Sep 2017 13:07:51 -0400","from mail-oi0-f43.google.com ([209.85.218.43]:34001 \"EHLO\n\tmail-oi0-f43.google.com\" rhost-flags-OK-OK-OK-OK) by vger.kernel.org\n\twith ESMTP id S1751480AbdIERHt (ORCPT\n\t); Tue, 5 Sep 2017 13:07:49 -0400","by mail-oi0-f43.google.com with SMTP id h70so28481851oic.1\n\tfor ;\n\tTue, 05 Sep 2017 10:07:49 -0700 (PDT)","by 10.157.35.33 with HTTP; Tue, 5 Sep 2017 10:07:48 -0700 (PDT)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=intel-com.20150623.gappssmtp.com; s=20150623;\n\th=mime-version:in-reply-to:references:from:date:message-id:subject:to\n\t:cc; bh=LLFnmSh2vUa1ShTSUkoa+lYxAEjbQqYqLgfVXejWtEk=;\n\tb=KHvW5YbwjLe4YSiaOHlKogeZEpHwBlZUSyO9HAFDd3keLxdZBqjtXn7QNG7euE9aQe\n\tPE/pcTkGE8kGhg8pA80vW7+Sz3iILJPnqevtLkmG2dj5v0W1ehVv5yBTDSxSscgLsjLr\n\tFrTsyBSsp8kxUhTswirlBBqG6LLV9+uoYukdwwopa8GQwA2YLBo/Xa0x4KU5Ch0tEZXi\n\tBJC/h33NKODLZEsSf8UwAhh33Gfk+6n/6k/Ng7S32BvCVdwWQoBOS6njQlJbYc3dNQXC\n\tCXyz0Ilpt7VvI8mFHX/D6n4A7HYPy5XwaHvACelDjBRyAgJZ9Kep1F636gaUzz/HosJ4\n\togLg==","X-Google-DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=1e100.net; s=20161025;\n\th=x-gm-message-state:mime-version:in-reply-to:references:from:date\n\t:message-id:subject:to:cc;\n\tbh=LLFnmSh2vUa1ShTSUkoa+lYxAEjbQqYqLgfVXejWtEk=;\n\tb=ozh1EHW75+3rzj+73yKw5S98fL9A0aBJc1iV2iUC4I4JoweHcnPi8WC/qe5oOboT+0\n\td8O086Z1ETqAjeqz98nIqHt1lUhFvSd07sNDgn/EZt9+uRZY9T57NgGYIsaCw5vcdZe2\n\tVu0IH9lHeZzbNsfqJeMMTCTUmlW1aakDVbbSWjzVEe+o5+zObGyhfhDubIYXodjrgqAV\n\tPK3JwrDT6wiBTEm+nastMfgz9/0Am444Rm5BoZ2kg8SHP2aHtLvFQ1X4NkyzI/yOcJvH\n\t31QcoQ98pjB7go2nvR+X7E9DssAcfhK1UYlmzCEKSBnCv/r2UJuIXiHAh8lGj18Py1my\n\tDJzg==","X-Gm-Message-State":"AHPjjUgvzzJU35LW/D1AeGI8iqtHGd6PKbK5Dp7JeTRwOEkRQAXrAWIk\n\tB5XffWAXHgv2HTanNPTjebxDuJu8bsly","X-Google-Smtp-Source":"ADKCNb5SxjdAT6mPoX9nCAt2DZ2SKxgSCMcalg7ycIY5ZB+dvQ1/m/3BUo5ufMqe03KO3osrhoQfH1z5O/mnGlpXDro=","X-Received":"by 10.202.79.198 with SMTP id d189mr4312876oib.48.1504631268794; \n\tTue, 05 Sep 2017 10:07:48 -0700 (PDT)","MIME-Version":"1.0","In-Reply-To":"<20170905165123.22245-1-colin.king@canonical.com>","References":"<20170905165123.22245-1-colin.king@canonical.com>","From":"Dan Williams ","Date":"Tue, 5 Sep 2017 10:07:48 -0700","Message-ID":"","Subject":"Re: [PATCH][ext4-next] ext4: fix null pointer dereference on sbi","To":"Colin King ","Cc":"\"Theodore Ts'o\" ,\n\tAndreas Dilger ,\n\tlinux-ext4 , kernel-janitors@vger.kernel.org,\n\t\"linux-kernel@vger.kernel.org\" ","Content-Type":"text/plain; charset=\"UTF-8\"","Sender":"linux-ext4-owner@vger.kernel.org","Precedence":"bulk","List-ID":"","X-Mailing-List":"linux-ext4@vger.kernel.org"}}]