From mboxrd@z Thu Jan 1 00:00:00 1970 From: Colin King Subject: [PATCH][ext4-next] ext4: fix null pointer dereference on sbi Date: Tue, 5 Sep 2017 17:51:23 +0100 Message-ID: <20170905165123.22245-1-colin.king@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, Dan Williams To: Theodore Ts'o , Andreas Dilger , linux-ext4@vger.kernel.org Return-path: Received: from youngberry.canonical.com ([91.189.89.112]:51638 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752191AbdIEQv1 (ORCPT ); Tue, 5 Sep 2017 12:51:27 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: From: Colin Ian King In the case of a kzalloc failure when allocating sbi we end up with a null pointer dereference on sbi when assigning sbi->s_daxdev. Fix this by moving the assignment of sbi->s_daxdev to after the null pointer check of sbi. Detected by CoverityScan CID#1455379 ("Dereference before null check") Fixes: 5e405595e5bf ("ext4: perform dax_device lookup at mount") Signed-off-by: Colin Ian King --- fs/ext4/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 0e63fcd12c5b..71b9a667e1bc 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3422,10 +3422,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO; ext4_group_t first_not_zeroed; - sbi->s_daxdev = dax_dev; if ((data && !orig_data) || !sbi) goto out_free_base; + sbi->s_daxdev = dax_dev; sbi->s_blockgroup_lock = kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL); if (!sbi->s_blockgroup_lock) -- 2.14.1