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Message-ID: <477DE2F9.2050208@simon.arlott.org.uk>
Date: Fri, 04 Jan 2008 07:40:41 +0000
From: Simon Arlott <simon@...e.lp0.eu>
To: Jan Kara <jack@...e.cz>
CC: Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Andrew Morton <akpm@...ux-foundation.org>,
folkert@...heusden.com, linux-kernel@...r.kernel.org
Subject: Re: [2.6.22] circular lock detected
On 25/09/07 09:46, Jan Kara wrote:
> On Tue 25-09-07 10:02:43, Peter Zijlstra wrote:
>> On Mon, 3 Sep 2007 16:01:35 +0200 Jan Kara <jack@...e.cz> wrote:
>>
>> > On Mon 03-09-07 05:49:59, Andrew Morton wrote:
>> > > > On Mon, 3 Sep 2007 14:27:02 +0200 Jan Kara <jack@...e.cz> wrote:
>> > > > > > On Fri, 24 Aug 2007 23:00:33 +0200 Folkert van Heusden <folkert@...heusden.com> wrote:
>>
>> > > > > Has been reported before, but I don't recall whether we fixed it. Jan,
>> > > > > do you know>?
>> > > > I think we at least found a solution: Teach lockdep that I_MUTEX for
>> > > > different filesystems is different. Peter Zilstra wrote a patch for that
>> > > > and Folkert even confirmed that it fixes the problem for him. I'm not
>> > > > sure what happened with the patch afterwards though. Adding Peter to CC
>> > > > :).
>> > >
>> > > But this is a tty_lock-versus-dqptr_sem ranking error. Unrelated to i_mutex?
>> > The final report is for this ranking but the locking chain (if I understand it
>> > right) is:
>> > tty_mutex (con_close) -> i_mutex (sysfs: remove_subdir)
>> > i_mutex (do_truncate) -> i_alloc_sem (notify_change) -> truncate_mutex (ext3_truncate)
>> > truncate_mutex (ext3_get_blocks_handle) -> dqptr_sem (dquot_alloc_space)
>> >
>> > So it complains about tty_mutex vs dqptr_sem (I don't know why it does not
>> > complain about tty_mutex vs i_mutex) but the wrong link in the chain is
>> > that i_mutex from remove_subdir() [sysfs] and i_mutex from do_truncate()
>> > [ext3] are different and should never depend on each other...
>> >
>>
>> Found it again.
> Cool, thanks Peter. Andrew, would you put it into -mm? This should take care of
> the false lockdep warnings from the quota code. If I recall correctly, one
> of the reporters even confirmed it fixes the problem for him.
> The patch looks fine. You can add:
> Signed-off-by: Jan Kara <jack@...e.cz>
>
> Honza
>
>> Give each filesystem its own inode lock class. The various filesystems have
>> different locking order wrt the inode locks; esp. the pseudo filesystems
>> differ from the rest.
>>
>> Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
This patch still doesn't exist in 2.6.23.9 and the warning isn't fixed...
03 00:31:34 [1905219.899008] =======================================================
03 00:31:34 [1905219.907136] [ INFO: possible circular locking dependency detected ]
03 00:31:34 [1905219.913569] 2.6.23.9-git #43
03 00:31:34 [1905219.916624] -------------------------------------------------------
03 00:31:34 [1905219.923059] bacula-sd/32639 is trying to acquire lock:
03 00:31:34 [1905219.928364] (tty_mutex){--..}, at: [<80389fd7>] mutex_lock+0x1c/0x1f
03 00:31:34 [1905219.935047]
03 00:31:34 [1905219.935049] but task is already holding lock:
03 00:31:34 [1905219.941238] (&s->s_dquot.dqptr_sem){----}, at: [<801839bf>] dquot_alloc_space+0x42/0x15b
03 00:31:34 [1905219.949646]
03 00:31:34 [1905219.949649] which lock already depends on the new lock.
03 00:31:34 [1905219.949652]
03 00:31:34 [1905219.958367]
03 00:31:34 [1905219.958369] the existing dependency chain (in reverse order) is:
03 00:31:34 [1905219.966204]
03 00:31:34 [1905219.966206] -> #4 (&s->s_dquot.dqptr_sem){----}:
03 00:31:34 [1905219.972714] [<80131c5b>] __lock_acquire+0x9ba/0xb96
03 00:31:34 [1905219.978511] [<80132200>] lock_acquire+0x5d/0x75
03 00:31:34 [1905219.983957] [<8012ac3c>] down_read+0x3a/0x4b
03 00:31:34 [1905219.989252] [<801839bf>] dquot_alloc_space+0x42/0x15b
03 00:31:34 [1905219.995217] [<801920e1>] ext3_new_blocks+0x83/0x5ba
03 00:31:34 [1905220.001009] [<80195111>] ext3_get_blocks_handle+0x386/0x822
03 00:31:34 [1905220.007495] [<80195889>] ext3_get_block+0xac/0xc5
03 00:31:34 [1905220.013113] [<80174e54>] __block_prepare_write+0x151/0x3c6
03 00:31:34 [1905220.019603] [<801750ed>] block_prepare_write+0x24/0x32
03 00:31:34 [1905220.025654] [<80196a43>] ext3_prepare_write+0x98/0x153
03 00:31:34 [1905220.031705] [<8013cbbe>] generic_file_buffered_write+0x219/0x57c
03 00:31:34 [1905220.038630] [<8013d384>] __generic_file_aio_write_nolock+0x463/0x4b3
03 00:31:34 [1905220.045894] [<8013d42a>] generic_file_aio_write+0x56/0xb4
03 00:31:34 [1905220.052292] [<8019311b>] ext3_file_write+0x27/0x99
03 00:31:34 [1905220.057996] [<80157742>] do_sync_write+0xc4/0x101
03 00:31:34 [1905220.063615] [<80157f03>] vfs_write+0xaf/0x138
03 00:31:34 [1905220.068885] [<8015840f>] sys_write+0x3d/0x61
03 00:31:34 [1905220.074071] [<80102702>] sysenter_past_esp+0x5f/0x99
03 00:31:34 [1905220.080046] [<ffffffff>] 0xffffffff
03 00:31:34 [1905220.084456]
03 00:31:34 [1905220.084458] -> #3 (&ei->truncate_mutex){--..}:
03 00:31:34 [1905220.090781] [<80131c5b>] __lock_acquire+0x9ba/0xb96
03 00:31:34 [1905220.096573] [<80132200>] lock_acquire+0x5d/0x75
03 00:31:34 [1905220.102020] [<80389e25>] __mutex_lock_slowpath+0xdb/0x271
03 00:31:34 [1905220.108418] [<80389fd7>] mutex_lock+0x1c/0x1f
03 00:31:34 [1905220.113690] [<80196110>] ext3_truncate+0x49e/0x7ec
03 00:31:34 [1905220.119397] [<80148496>] vmtruncate+0x161/0x187
03 00:31:34 [1905220.124847] [<80169794>] inode_setattr+0x73/0x149
03 00:31:34 [1905220.130470] [<8019720c>] ext3_setattr+0x185/0x1e1
03 00:31:34 [1905220.136088] [<8016999a>] notify_change+0x130/0x2d2
03 00:31:34 [1905220.141883] [<80156c7b>] do_truncate+0x60/0x79
03 00:31:34 [1905220.147245] [<8015f377>] may_open+0x1b9/0x201
03 00:31:34 [1905220.152522] [<801612e3>] open_namei+0x240/0x539
03 00:31:34 [1905220.157965] [<8015651b>] do_filp_open+0x26/0x3b
03 00:31:34 [1905220.163411] [<80156575>] do_sys_open+0x45/0xc9
03 00:31:34 [1905220.168857] [<80156631>] sys_open+0x1c/0x1e
03 00:31:34 [1905220.173955] [<80102702>] sysenter_past_esp+0x5f/0x99
03 00:31:34 [1905220.179830] [<ffffffff>] 0xffffffff
03 00:31:34 [1905220.184233]
03 00:31:34 [1905220.184235] -> #2 (&inode->i_alloc_sem){--..}:
03 00:31:34 [1905220.190559] [<80131c5b>] __lock_acquire+0x9ba/0xb96
03 00:31:34 [1905220.196436] [<80132200>] lock_acquire+0x5d/0x75
03 00:31:34 [1905220.201884] [<8012acd6>] down_write+0x3a/0x53
03 00:31:34 [1905220.207152] [<80169952>] notify_change+0xe8/0x2d2
03 00:31:34 [1905220.212772] [<80156c7b>] do_truncate+0x60/0x79
03 00:31:34 [1905220.218130] [<8015f377>] may_open+0x1b9/0x201
03 00:31:34 [1905220.223485] [<801612e3>] open_namei+0x240/0x539
03 00:31:34 [1905220.228926] [<8015651b>] do_filp_open+0x26/0x3b
03 00:31:34 [1905220.234372] [<80156575>] do_sys_open+0x45/0xc9
03 00:31:34 [1905220.239727] [<80156631>] sys_open+0x1c/0x1e
03 00:31:34 [1905220.244819] [<80102702>] sysenter_past_esp+0x5f/0x99
03 00:31:34 [1905220.250760] [<ffffffff>] 0xffffffff
03 00:31:34 [1905220.255156]
03 00:31:34 [1905220.255158] -> #1 (&inode->i_mutex){--..}:
03 00:31:34 [1905220.261135] [<80131c5b>] __lock_acquire+0x9ba/0xb96
03 00:31:34 [1905220.268005] [<80132200>] lock_acquire+0x5d/0x75
03 00:31:34 [1905220.273448] [<80389e25>] __mutex_lock_slowpath+0xdb/0x271
03 00:31:34 [1905220.279752] [<80389fd7>] mutex_lock+0x1c/0x1f
03 00:31:34 [1905220.285024] [<80190cf6>] get_node+0x1d/0x46
03 00:31:34 [1905220.290119] [<80190e84>] devpts_get_tty+0xb/0x3b
03 00:31:34 [1905220.295646] [<80214fb5>] init_dev+0x21/0x4a2
03 00:31:34 [1905220.300837] [<80217c95>] ptmx_open+0xfd/0x1bc
03 00:31:34 [1905220.306102] [<80159f91>] chrdev_open+0x14a/0x180
03 00:31:34 [1905220.311618] [<801563b2>] __dentry_open+0xfd/0x1af
03 00:31:34 [1905220.317232] [<801564e5>] nameidata_to_filp+0x27/0x37
03 00:31:34 [1905220.323097] [<80156528>] do_filp_open+0x33/0x3b
03 00:31:34 [1905220.328535] [<80156575>] do_sys_open+0x45/0xc9
03 00:31:34 [1905220.333874] [<80156631>] sys_open+0x1c/0x1e
03 00:31:34 [1905220.338981] [<80102702>] sysenter_past_esp+0x5f/0x99
03 00:31:34 [1905220.344855] [<ffffffff>] 0xffffffff
03 00:31:34 [1905220.349256]
03 00:31:34 [1905220.349258] -> #0 (tty_mutex){--..}:
03 00:31:34 [1905220.354717] [<80131b4b>] __lock_acquire+0x8aa/0xb96
03 00:31:34 [1905220.360505] [<80132200>] lock_acquire+0x5d/0x75
03 00:31:34 [1905220.365956] [<80389e25>] __mutex_lock_slowpath+0xdb/0x271
03 00:31:34 [1905220.372258] [<80389fd7>] mutex_lock+0x1c/0x1f
03 00:31:34 [1905220.377517] [<80182ea9>] print_warning+0x92/0x137
03 00:31:34 [1905220.383139] [<80183ab8>] dquot_alloc_space+0x13b/0x15b
03 00:31:34 [1905220.389176] [<801920e1>] ext3_new_blocks+0x83/0x5ba
03 00:31:34 [1905220.394961] [<80195111>] ext3_get_blocks_handle+0x386/0x822
03 00:31:34 [1905220.401429] [<80195889>] ext3_get_block+0xac/0xc5
03 00:31:34 [1905220.407047] [<80174e54>] __block_prepare_write+0x151/0x3c6
03 00:31:34 [1905220.413455] [<801750ed>] block_prepare_write+0x24/0x32
03 00:31:34 [1905220.419506] [<80196a43>] ext3_prepare_write+0x98/0x153
03 00:31:34 [1905220.425553] [<8013cbbe>] generic_file_buffered_write+0x219/0x57c
03 00:31:34 [1905220.432465] [<8013d384>] __generic_file_aio_write_nolock+0x463/0x4b3
03 00:31:34 [1905220.439724] [<8013d42a>] generic_file_aio_write+0x56/0xb4
03 00:31:34 [1905220.446027] [<8019311b>] ext3_file_write+0x27/0x99
03 00:31:34 [1905220.451728] [<80157742>] do_sync_write+0xc4/0x101
03 00:31:34 [1905220.457338] [<80157f03>] vfs_write+0xaf/0x138
03 00:31:34 [1905220.462600] [<8015840f>] sys_write+0x3d/0x61
03 00:31:34 [1905220.467771] [<80102702>] sysenter_past_esp+0x5f/0x99
03 00:31:34 [1905220.473639] [<ffffffff>] 0xffffffff
03 00:31:34 [1905220.478040]
03 00:31:34 [1905220.478043] other info that might help us debug this:
03 00:31:34 [1905220.478046]
03 00:31:34 [1905220.486588] 3 locks held by bacula-sd/32639:
03 00:31:34 [1905220.491025] #0: (&inode->i_mutex){--..}, at: [<80389fd7>] mutex_lock+0x1c/0x1f
03 00:31:34 [1905220.498668] #1: (&ei->truncate_mutex){--..}, at: [<80389fd7>] mutex_lock+0x1c/0x1f
03 00:31:34 [1905220.506659] #2: (&s->s_dquot.dqptr_sem){----}, at: [<801839bf>] dquot_alloc_space+0x42/0x15b
03 00:31:34 [1905220.515511]
03 00:31:34 [1905220.515513] stack backtrace:
03 00:31:34 [1905220.520230] [<80103694>] show_trace_log_lvl+0x1a/0x2f
03 00:31:34 [1905220.525555] [<8010421b>] show_trace+0x12/0x14
03 00:31:34 [1905220.530185] [<80104232>] dump_stack+0x15/0x17
03 00:31:34 [1905220.534817] [<801303c4>] print_circular_bug_tail+0x5e/0x67
03 00:31:34 [1905220.540580] [<80131b4b>] __lock_acquire+0x8aa/0xb96
03 00:31:34 [1905220.545731] [<80132200>] lock_acquire+0x5d/0x75
03 00:31:34 [1905220.550536] [<80389e25>] __mutex_lock_slowpath+0xdb/0x271
03 00:31:34 [1905220.556203] [<80389fd7>] mutex_lock+0x1c/0x1f
03 00:31:34 [1905220.560838] [<80182ea9>] print_warning+0x92/0x137
03 00:31:34 [1905220.565819] [<80183ab8>] dquot_alloc_space+0x13b/0x15b
03 00:31:34 [1905220.571230] [<801920e1>] ext3_new_blocks+0x83/0x5ba
03 00:31:34 [1905220.576381] [<80195111>] ext3_get_blocks_handle+0x386/0x822
03 00:31:34 [1905220.582226] [<80195889>] ext3_get_block+0xac/0xc5
03 00:31:34 [1905220.587205] [<80174e54>] __block_prepare_write+0x151/0x3c6
03 00:31:34 [1905220.592963] [<801750ed>] block_prepare_write+0x24/0x32
03 00:31:34 [1905220.598372] [<80196a43>] ext3_prepare_write+0x98/0x153
03 00:31:34 [1905220.603785] [<8013cbbe>] generic_file_buffered_write+0x219/0x57c
03 00:31:34 [1905220.610063] [<8013d384>] __generic_file_aio_write_nolock+0x463/0x4b3
03 00:31:34 [1905220.616687] [<8013d42a>] generic_file_aio_write+0x56/0xb4
03 00:31:34 [1905220.622362] [<8019311b>] ext3_file_write+0x27/0x99
03 00:31:34 [1905220.627426] [<80157742>] do_sync_write+0xc4/0x101
03 00:31:34 [1905220.632401] [<80157f03>] vfs_write+0xaf/0x138
03 00:31:34 [1905220.637033] [<8015840f>] sys_write+0x3d/0x61
03 00:31:34 [1905220.641574] [<80102702>] sysenter_past_esp+0x5f/0x99
03 00:31:34 [1905220.646811] =======================
>> ---
>> fs/inode.c | 12 +++++++++---
>> include/linux/fs.h | 5 +++++
>> 2 files changed, 14 insertions(+), 3 deletions(-)
>>
>> Index: linux-2.6/fs/inode.c
>> ===================================================================
>> --- linux-2.6.orig/fs/inode.c
>> +++ linux-2.6/fs/inode.c
>> @@ -142,6 +142,15 @@ static struct inode *alloc_inode(struct
>> return NULL;
>> }
>>
>> + spin_lock_init(&inode->i_lock);
>> + lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);
>> +
>> + mutex_init(&inode->i_mutex);
>> + lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);
>> +
>> + init_rwsem(&inode->i_alloc_sem);
>> + lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key);
>> +
>> mapping->a_ops = &empty_aops;
>> mapping->host = inode;
>> mapping->flags = 0;
>> @@ -190,8 +199,6 @@ void inode_init_once(struct inode *inode
>> INIT_HLIST_NODE(&inode->i_hash);
>> INIT_LIST_HEAD(&inode->i_dentry);
>> INIT_LIST_HEAD(&inode->i_devices);
>> - mutex_init(&inode->i_mutex);
>> - init_rwsem(&inode->i_alloc_sem);
>> INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
>> rwlock_init(&inode->i_data.tree_lock);
>> spin_lock_init(&inode->i_data.i_mmap_lock);
>> @@ -199,7 +206,6 @@ void inode_init_once(struct inode *inode
>> spin_lock_init(&inode->i_data.private_lock);
>> INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap);
>> INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear);
>> - spin_lock_init(&inode->i_lock);
>> i_size_ordered_init(inode);
>> #ifdef CONFIG_INOTIFY
>> INIT_LIST_HEAD(&inode->inotify_watches);
>> Index: linux-2.6/include/linux/fs.h
>> ===================================================================
>> --- linux-2.6.orig/include/linux/fs.h
>> +++ linux-2.6/include/linux/fs.h
>> @@ -1302,8 +1302,13 @@ struct file_system_type {
>> struct module *owner;
>> struct file_system_type * next;
>> struct list_head fs_supers;
>> +
>> struct lock_class_key s_lock_key;
>> struct lock_class_key s_umount_key;
>> +
>> + struct lock_class_key i_lock_key;
>> + struct lock_class_key i_mutex_key;
>> + struct lock_class_key i_alloc_sem_key;
>> };
>>
>> extern int get_sb_bdev(struct file_system_type *fs_type,
>>
--
Simon Arlott
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