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From: "tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org" <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Cc: shyju pv <shyju.pv-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>,
	"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Sanil kumar <sanil.kumar-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>,
	Masanari Iida
	<standby24x7-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: 3.5-rc3: BUG: Dentry still in use (1) [unmount of cgroup cgroup]
Date: Thu, 28 Jun 2012 11:07:12 -0700	[thread overview]
Message-ID: <20120628180712.GC22641@google.com> (raw)
In-Reply-To: <4FEBF4B7.2070105-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>

Hello, Li.

On Thu, Jun 28, 2012 at 02:07:51PM +0800, Li Zefan wrote:
> > Hmm... fa980ca87d "cgroup: superblock can't be released with active
> > dentries" is supposed to have fixed that.  Looking into it.
> > 
> 
> 
> I think I know what happened here:
> 
> umount
>   deativate_super(sb)
>                        dput(subdir)
>                          subdir->d_count--
>                          d_release(subdir)
>                            deactivate_super(sb)
>                              shrink_dcache_for_umount(sb)
>                                BUG(root->d_count)!!
>                          root->d_count--

Can you please elaborate a bit?  I'm not really following?  Where does
the last root->d_count-- come from?

> I use this script to reproduce the bug:
> 
> mount -t cgroup -o cpu xxx /mnt
> mkdir /mnt/sub
> sleep 100 < /mnt/sub &
> kill $!
> wait $!
> rmdir /mnt/sub
> umount /mnt

Unfortunately, this doesn't reproduce the bug here either. :(

Thanks.

-- 
tejun

WARNING: multiple messages have this Message-ID (diff)
From: "tj@kernel.org" <tj@kernel.org>
To: Li Zefan <lizefan@huawei.com>
Cc: shyju pv <shyju.pv@huawei.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
	Sanil kumar <sanil.kumar@huawei.com>,
	Masanari Iida <standby24x7@gmail.com>
Subject: Re: 3.5-rc3: BUG: Dentry still in use (1) [unmount of cgroup cgroup]
Date: Thu, 28 Jun 2012 11:07:12 -0700	[thread overview]
Message-ID: <20120628180712.GC22641@google.com> (raw)
In-Reply-To: <4FEBF4B7.2070105@huawei.com>

Hello, Li.

On Thu, Jun 28, 2012 at 02:07:51PM +0800, Li Zefan wrote:
> > Hmm... fa980ca87d "cgroup: superblock can't be released with active
> > dentries" is supposed to have fixed that.  Looking into it.
> > 
> 
> 
> I think I know what happened here:
> 
> umount
>   deativate_super(sb)
>                        dput(subdir)
>                          subdir->d_count--
>                          d_release(subdir)
>                            deactivate_super(sb)
>                              shrink_dcache_for_umount(sb)
>                                BUG(root->d_count)!!
>                          root->d_count--

Can you please elaborate a bit?  I'm not really following?  Where does
the last root->d_count-- come from?

> I use this script to reproduce the bug:
> 
> mount -t cgroup -o cpu xxx /mnt
> mkdir /mnt/sub
> sleep 100 < /mnt/sub &
> kill $!
> wait $!
> rmdir /mnt/sub
> umount /mnt

Unfortunately, this doesn't reproduce the bug here either. :(

Thanks.

-- 
tejun

  parent reply	other threads:[~2012-06-28 18:07 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-24 19:08 3.5-rc3: BUG: Dentry still in use (1) [unmount of cgroup cgroup] shyju pv
2012-06-24 19:08 ` shyju pv
     [not found] ` <E061084CB90FCE4F89232A6CF839683B32B52291-SY/3K1LPFSqBBfbIEMVH7QK1hpo4iccwjNknBlVQO8k@public.gmane.org>
2012-06-26 23:00   ` Masanari Iida
2012-06-26 23:00     ` Masanari Iida
2012-06-27 18:29   ` tj-DgEjT+Ai2ygdnm+yROfE0A
2012-06-27 18:29     ` tj
     [not found]     ` <20120627182903.GP15811-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-06-27 23:02       ` tj-DgEjT+Ai2ygdnm+yROfE0A
2012-06-27 23:02         ` tj
     [not found]         ` <20120627230230.GT15811-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-06-28 14:09           ` Masanari Iida
2012-06-28 14:09             ` Masanari Iida
2012-06-28  6:07     ` Li Zefan
2012-06-28  6:07     ` Li Zefan
     [not found]       ` <4FEBF4B7.2070105-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2012-06-28 18:07         ` tj-DgEjT+Ai2ygdnm+yROfE0A [this message]
2012-06-28 18:07           ` tj
     [not found]           ` <20120628180712.GC22641-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-06-29  2:20             ` Li Zefan
2012-06-29  2:20               ` Li Zefan
     [not found]               ` <4FED10DB.7040500-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2012-06-29 16:58                 ` tj-DgEjT+Ai2ygdnm+yROfE0A
2012-06-29 16:58                   ` tj
2012-06-29 18:07                   ` Masanari Iida
     [not found]                   ` <20120629165809.GB21048-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-06-30  6:13                     ` Li Zefan
2012-06-30  6:13                       ` Li Zefan
     [not found]                       ` <4FEE98EE.1050409-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2012-06-30  6:47                         ` Al Viro
2012-06-30  6:47                           ` Al Viro
     [not found]                           ` <20120630064724.GC14083-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2012-06-30  7:04                             ` Tejun Heo
2012-06-30  7:04                               ` Tejun Heo
     [not found]                               ` <CAOS58YNnU3J+c2ZQcRCesSoxn0dSJjDLBsZ2qzZ09X6N-ky0fQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-06-30  8:34                                 ` Al Viro
2012-06-30  8:34                                   ` Al Viro
     [not found]                                   ` <20120630083421.GD14083-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2012-07-03 17:10                                     ` Tejun Heo
2012-07-03 17:10                                       ` Tejun Heo
     [not found]                                       ` <20120703171033.GC555-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-07-03 17:38                                         ` [PATCH] cgroup: cgroup_rm_files() was calling simple_unlink() with the wrong inode Tejun Heo
2012-07-03 17:38                                           ` Tejun Heo
     [not found]                                           ` <20120703173806.GD555-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-07-04  5:40                                             ` Li Zefan
2012-07-04  5:40                                               ` Li Zefan
     [not found]                                               ` <4FF3D757.9060905-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2012-07-09 17:11                                                 ` Tejun Heo
2012-07-09 17:11                                                   ` Tejun Heo

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