From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758149Ab0DVUBw (ORCPT ); Thu, 22 Apr 2010 16:01:52 -0400 Received: from kroah.org ([198.145.64.141]:59899 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757728Ab0DVUBL (ORCPT ); Thu, 22 Apr 2010 16:01:11 -0400 X-Mailbox-Line: From gregkh@kvm.kroah.org Thu Apr 22 12:54:14 2010 Message-Id: <20100422195414.678552487@kvm.kroah.org> User-Agent: quilt/0.48-4.4 Date: Thu, 22 Apr 2010 12:54:31 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Sachin Prabhu , Eric Van Hensbergen , maximilian attems Subject: [094/139] 9p: Skip check for mandatory locks when unlocking In-Reply-To: <20100422195715.GA25490@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.33-stable review patch. If anyone has any objections, please let us know. ------------------ From: Sachin Prabhu commit f78233dd44a110c574fe760ad6f9c1e8741a0d00 upstream. While investigating a bug, I came across a possible bug in v9fs. The problem is similar to the one reported for NFS by ASANO Masahiro in http://lkml.org/lkml/2005/12/21/334. v9fs_file_lock() will skip locks on file which has mode set to 02666. This is a problem in cases where the mode of the file is changed after a process has obtained a lock on the file. Such a lock will be skipped during unlock and the machine will end up with a BUG in locks_remove_flock(). v9fs_file_lock() should skip the check for mandatory locks when unlocking a file. Signed-off-by: Sachin Prabhu Signed-off-by: Eric Van Hensbergen Cc: maximilian attems Signed-off-by: Greg Kroah-Hartman --- fs/9p/vfs_file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -114,7 +114,7 @@ static int v9fs_file_lock(struct file *f P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl); /* No mandatory locks */ - if (__mandatory_lock(inode)) + if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK) return -ENOLCK; if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {