From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763785AbXFBTQf (ORCPT ); Sat, 2 Jun 2007 15:16:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758490AbXFBTQ3 (ORCPT ); Sat, 2 Jun 2007 15:16:29 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:47818 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757301AbXFBTQ2 (ORCPT ); Sat, 2 Jun 2007 15:16:28 -0400 Date: Sat, 2 Jun 2007 12:16:16 -0700 From: Andrew Morton To: Cyrill Gorcunov Cc: Eric Sandeen , Jan Kara , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] Fix possible leakage of blocks in UDF Message-Id: <20070602121616.37ffce9e.akpm@linux-foundation.org> In-Reply-To: <20070602185707.GA8518@cvg> References: <46609FBD.5040407@sandeen.net> <20070601154834.53558d1b.akpm@linux-foundation.org> <4660FD7F.4090302@sandeen.net> <20070601224339.c803e04e.akpm@linux-foundation.org> <20070602063403.GA8387@cvg> <20070601235422.fdc1f750.akpm@linux-foundation.org> <20070602065923.GB8387@cvg> <20070602000645.508ddf93.akpm@linux-foundation.org> <20070602140619.GA10303@cvg> <20070602103203.e39d25ed.akpm@linux-foundation.org> <20070602185707.GA8518@cvg> X-Mailer: Sylpheed 2.4.1 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2 Jun 2007 22:57:07 +0400 Cyrill Gorcunov wrote: > [Andrew Morton - Sat, Jun 02, 2007 at 10:32:03AM -0700] > | On Sat, 2 Jun 2007 18:06:19 +0400 Cyrill Gorcunov wrote: > | > | > [Andrew Morton - Sat, Jun 02, 2007 at 12:06:45AM -0700] > | > | On Sat, 2 Jun 2007 10:59:23 +0400 Cyrill Gorcunov wrote: > | > | > | > | > [Andrew Morton - Fri, Jun 01, 2007 at 11:54:22PM -0700] > | > | > | On Sat, 2 Jun 2007 10:34:03 +0400 Cyrill Gorcunov wrote: > | > | > | > | > | > | > | That patch is DOA, methinks. > | > | > | > | > | > | > | > > | > | > | > Andrew, what does it mean - "DOA"? Dead on arrival? > | > | > | > | > | > | yes - I dropped it. > | > | > | > | > | > > | > | > But that could lead to rejection of my code-style-conversion patch... > | > | > Should I remake them? > | > | > | > | Actually I've rebuilt those patches four times already. People keep > | > | changing stuff. > | > | > | > | > Actually Jan was right, the current state of UDF (without his patches) > | > | > could lead to lost blocks and his patch must be just fixed I think. > | > | > | > | sure. > | > | > | > > | > Andrew, you know I've been trying to reproduce Eric's lockup case almost > | > two hour and still can't reach it. All manupulation I've done to UDF didn't > | > lead to lockup. Moreover, I've added debug print for UDF module and here is > | > the results (for single drop_inode call): > | > > | > [12063.897000] UDF: udf_drop_inode:105 --> udf_drop_inode --> inode->i_count: 0 > | > [12063.897000] UDF: udf_drop_inode:107 udf_drop_inode -> discard_prealloc > | > [12063.897000] UDF: udf_discard_prealloc:136 udf_discard_prealloc > | > [12063.897000] UDF: udf_truncate_tail_extent:84 udf_truncate_tail_extent > | > [12063.897000] UDF: udf_truncate_extents:194 udf_truncate_extents --> > | > [12063.897000] UDF: extent_trunc:38 ---> > | > [12063.897000] UDF: extent_trunc:54 call to udf_write_aext > | > [12063.897000] UDF: udf_write_aext:1843 udf_write_aext > | > [12063.897000] UDF: udf_write_aext:1846 dont has epos->bh > | > [12063.897000] UDF: udf_write_aext:1866 ICBTAG_FLAG_AD_LONG > | > ---> [12063.897000] UDF: udf_write_aext:1893 ---> gotcha ---> call mark_inode_dirty > | > ---> [12063.897000] UDF: extent_trunc:59 --> gotcha --> call mark_inode_dirty > | > [12063.897000] UDF: extent_trunc:68 <--- > | > ---> [12063.897000] UDF: udf_truncate_extents:282 call mark_inode_dirty > | > [12063.897000] UDF: udf_truncate_extents:330 udf_truncate_extents <-- > | > [12063.897000] UDF: udf_drop_inode:115 <-- udf_drop_inode <-- > | > > | > As you may see, mark_inode_dirty is called several time and no locking happened. > | > Maybe I should use some test utils? > | > > | > | Silly question: you _do_ have CONFIG_SMP=y, yes? > | > Oh, no I don't :( So the problem is in kernel sync (as I thought)... > damn... I have to rebuild my kernel... but hold on - my machine has only > one CPU ;) You should be able to run an SMP kernel on a single-CPU machine. > | And did you enable lockdep? > | > Yes > > So the problem is 'cause of mark_inode_dirty may sleep? Right? > So only thing to be checked is lock_kernel I think No, the problem is that the patch caused the kernel to take inode_lock within the newly-added drop_inode(), btu drop_inode() is already called under inode_lock. It has nothing to do with lock_kernel() and it has nothing to do with sleeping.