From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753334AbcEXVO6 (ORCPT ); Tue, 24 May 2016 17:14:58 -0400 Received: from 78-80-28-91.tmcz.cz ([78.80.28.91]:36262 "EHLO leontynka.twibright.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752284AbcEXVO5 (ORCPT ); Tue, 24 May 2016 17:14:57 -0400 Date: Tue, 24 May 2016 22:48:33 +0200 (CEST) From: Mikulas Patocka X-X-Sender: mikulas@leontynka To: Linus Torvalds cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 2/3] affs: fix remount failure when there are no options changed Message-ID: User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The patch c8f33d0bec99 ("affs: kstrdup() memory handling") checks if the kstrdup function returns NULL due to out-of-memory condition. However, if we are remounting a filesystem with no change to filesystem-specific options, the parameter data is NULL. In this case, kstrdup returns NULL (because it was passed NULL parameter), although no out of memory condition exists. The mount syscall then fails with ENOMEM. This patch fixes the bug. We fail with ENOMEM only if data is non-NULL. The patch also changes the call to replace_mount_options - if we didn't pass any filesystem-specific options, we don't call replace_mount_options (thus we don't erase existing reported options). Fixes: c8f33d0bec99 ("affs: kstrdup() memory handling") Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org # v4.1+ --- fs/affs/super.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) Index: linux-4.6/fs/affs/super.c =================================================================== --- linux-4.6.orig/fs/affs/super.c 2016-05-19 20:49:25.000000000 +0200 +++ linux-4.6/fs/affs/super.c 2016-05-19 20:56:21.000000000 +0200 @@ -528,7 +528,7 @@ affs_remount(struct super_block *sb, int char *prefix = NULL; new_opts = kstrdup(data, GFP_KERNEL); - if (!new_opts) + if (data && !new_opts) return -ENOMEM; pr_debug("%s(flags=0x%x,opts=\"%s\")\n", __func__, *flags, data); @@ -546,7 +546,8 @@ affs_remount(struct super_block *sb, int } flush_delayed_work(&sbi->sb_work); - replace_mount_options(sb, new_opts); + if (new_opts) + replace_mount_options(sb, new_opts); sbi->s_flags = mount_flags; sbi->s_mode = mode;