From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Zdenek Kabelac , Jan Kara , Al Viro Subject: [ 100/123] fs: Fix imbalance in freeze protection in mark_files_ro() Date: Wed, 9 Jan 2013 12:35:39 -0800 Message-Id: <20130109201511.401004489@linuxfoundation.org> In-Reply-To: <20130109201458.392601412@linuxfoundation.org> References: <20130109201458.392601412@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit 72651cac884b1e285fa8e8314b10e9f1b8458802 upstream. File descriptors (even those for writing) do not hold freeze protection. Thus mark_files_ro() must call __mnt_drop_write() to only drop protection against remount read-only. Calling mnt_drop_write_file() as we do now results in: [ BUG: bad unlock balance detected! ] 3.7.0-rc6-00028-g88e75b6 #101 Not tainted ------------------------------------- kworker/1:2/79 is trying to release lock (sb_writers) at: [] mnt_drop_write+0x24/0x30 but there are no more locks to release! Reported-by: Zdenek Kabelac Signed-off-by: Jan Kara Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- fs/file_table.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/file_table.c +++ b/fs/file_table.c @@ -458,8 +458,8 @@ void mark_files_ro(struct super_block *s spin_unlock(&f->f_lock); if (file_check_writeable(f) != 0) continue; + __mnt_drop_write(f->f_path.mnt); file_release_write(f); - mnt_drop_write_file(f); } while_file_list_for_each_entry; lg_global_unlock(&files_lglock); }