From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933567AbcHNLCA (ORCPT ); Sun, 14 Aug 2016 07:02:00 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51965 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964835AbcHNLB4 (ORCPT ); Sun, 14 Aug 2016 07:01:56 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Linus Torvalds" , "Mikulas Patocka" , "Mikulas Patocka" Date: Sat, 13 Aug 2016 18:42:51 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 129/305] hpfs: fix remount failure when there are no options changed In-Reply-To: X-SA-Exim-Connect-IP: 92.40.249.202 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.37-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Mikulas Patocka commit 44d51706b4685f965cd32acde3fe0fcc1e6198e8 upstream. Commit ce657611baf9 ("hpfs: kstrdup() out of 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: ce657611baf9 ("hpfs: kstrdup() out of memory handling") Signed-off-by: Mikulas Patocka Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- fs/hpfs/super.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/fs/hpfs/super.c +++ b/fs/hpfs/super.c @@ -428,7 +428,7 @@ static int hpfs_remount_fs(struct super_ struct hpfs_sb_info *sbi = hpfs_sb(s); char *new_opts = kstrdup(data, GFP_KERNEL); - if (!new_opts) + if (data && !new_opts) return -ENOMEM; sync_filesystem(s); @@ -466,7 +466,8 @@ static int hpfs_remount_fs(struct super_ if (!(*flags & MS_RDONLY)) mark_dirty(s, 1); - replace_mount_options(s, new_opts); + if (new_opts) + replace_mount_options(s, new_opts); hpfs_unlock(s); return 0;