lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Sat, 30 Jun 2012 00:04:36 -0700
From:	Tejun Heo <tj@...nel.org>
To:	Al Viro <viro@...iv.linux.org.uk>
Cc:	Li Zefan <lizefan@...wei.com>, shyju pv <shyju.pv@...wei.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"cgroups@...r.kernel.org" <cgroups@...r.kernel.org>,
	Sanil kumar <sanil.kumar@...wei.com>,
	Masanari Iida <standby24x7@...il.com>
Subject: Re: 3.5-rc3: BUG: Dentry still in use (1) [unmount of cgroup cgroup]

Hello, Al.

On Fri, Jun 29, 2012 at 11:47 PM, Al Viro <viro@...iv.linux.org.uk> wrote:
> On Sat, Jun 30, 2012 at 02:13:02PM +0800, Li Zefan wrote:
>> So it's bad to have dentry refcnts dangling after umount.
>
> No shit.  Yes, it is bad.  What on the Earth is cgroup code doing with
> those?  And what could it possibly want to do with dentry reference
> after the filesystem has been shut down, assuming it could hold one
> in the first place?

cgroup interface code was copied from sysfs back when it was
piggybacking internal data structures to dentries, so, unfortunately,
sysfs is still using dentries to manage internal data structures and
propagates internal refs to dentry refs. There seem to be several
places where dentry ref is held w/o active super ref triggering BUG on
umount. Longer term, it should be updated to share sysfs code, I
guess.

Thanks.

-- 
tejun
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ