Messages in this thread Patch in this message | | | Date | Tue, 25 Sep 2007 10:02:43 +0200 | From | Peter Zijlstra <> | Subject | Re: [2.6.22] circular lock detected |
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On Mon, 3 Sep 2007 16:01:35 +0200 Jan Kara <jack@suse.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@suse.cz> wrote: > > > > > On Fri, 24 Aug 2007 23:00:33 +0200 Folkert van Heusden <folkert@vanheusden.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.
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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@chello.nl> --- 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, - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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