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From: ebiederm@xmission.com (Eric W. Biederman)
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Tejun Heo <tj@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Borislav Petkov <petkovbb@googlemail.com>,
	David Airlie <airlied@linux.ie>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Greg KH <greg@kroah.com>, Al Viro <viro@ZenIV.linux.org.uk>
Subject: Re: drm_vm.c:drm_mmap: possible circular locking dependency detected
Date: Sun, 03 Jan 2010 03:14:18 -0800	[thread overview]
Message-ID: <m1d41rsanp.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <m1tyv3sbg4.fsf@fess.ebiederm.org> (Eric W. Biederman's message of "Sun\, 03 Jan 2010 02\:57\:15 -0800")

ebiederm@xmission.com (Eric W. Biederman) writes:

> What to do about it is another question.   It has just recently come to my
> attention that we have more events like this

In the specific case of serio what gets us in trouble is
the call to sysfs_remove_group.

If instead of independent calls to sysfs_create_group/sysfs_remove_group,
you could move the groups into a list on dev->groups than we could solve
two problems.

- Userspace would see all of the attributes when the hotplug event is
  fired remove races.

- We would not hold serio->drv_mutex over sysfs_remove_group so there
  would not be a possible deadlock on device removal.

Does that change sound possible?

Eric



  reply	other threads:[~2010-01-03 11:14 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-24 22:00 Linux 2.6.33-rc2 - Merry Christmas Linus Torvalds
2009-12-25 10:27 ` -tip: origin tree boot crash Ingo Molnar
2009-12-25 19:49   ` Dmitry Torokhov
2009-12-26 20:19     ` Len Brown
2009-12-26 20:17   ` Len Brown
2009-12-27  4:20     ` Len Brown
2009-12-28  9:44       ` Ingo Molnar
2009-12-28 12:01         ` Ingo Molnar
2009-12-28 15:02           ` Paul Rolland
2009-12-28 16:15             ` Paul Rolland
2009-12-28 16:53             ` Paul Rolland
2009-12-28 20:17               ` Dmitry Torokhov
2009-12-30  6:14               ` Len Brown
2009-12-30  7:13                 ` Paul Rolland
2009-12-30  6:19               ` [PATCH] wmi: check find_guid() return value to prevent oops Len Brown
2009-12-30  6:21               ` [PATCH] dell-wmi: sys_init_module: 'dell_wmi'->init suspiciously returned 21, it should follow 0/-E convention Len Brown
2009-12-25 13:10 ` Linux 2.6.33-rc2 - Blank screen for Intel KMS Miguel Calleja
2009-12-29  9:50   ` Miguel Calleja
2009-12-29 14:01     ` Rafael J. Wysocki
2009-12-25 20:00 ` Linux 2.6.33-rc2 - Merry Christmas Borislav Petkov
2009-12-25 21:50   ` Borislav Petkov
2009-12-26  6:00     ` Jesse Barnes
2009-12-26  8:02       ` Borislav Petkov
2009-12-26  9:36 ` EHCI resume sysfs duplicates (was: Re: Linux 2.6.33-rc2 - Merry Christmas ...) Borislav Petkov
2009-12-26  9:45 ` drm_vm.c:drm_mmap: possible circular locking dependency detected " Borislav Petkov
2009-12-28  0:40   ` KOSAKI Motohiro
2009-12-30 21:10     ` Linus Torvalds
2009-12-30 21:34       ` Eric W. Biederman
2009-12-30 22:03         ` Linus Torvalds
2009-12-31  8:40           ` Eric W. Biederman
2009-12-31 19:04             ` Linus Torvalds
2010-01-01 13:58               ` [PATCH] sysfs: Cache the last sysfs_dirent to improve readdir scalability Eric W. Biederman
2010-01-01 15:33                 ` Borislav Petkov
2010-01-01 18:56                 ` Linus Torvalds
2010-01-01 22:43                   ` [PATCH] sysfs: Cache the last sysfs_dirent to improve readdir scalability v2 Eric W. Biederman
2010-01-01 23:10                     ` Linus Torvalds
2010-01-02  5:59                       ` Greg KH
2010-01-02 15:40                       ` Borislav Petkov
2010-01-01 15:16               ` drm_vm.c:drm_mmap: possible circular locking dependency detected (was: Re: Linux 2.6.33-rc2 - Merry Christmas ...) Eric W. Biederman
2010-01-02  2:59                 ` drm_vm.c:drm_mmap: possible circular locking dependency detected Tejun Heo
2010-01-02 21:37                   ` [PATCH] sysfs: Add lockdep annotations for the sysfs active reference Eric W. Biederman
2010-01-03  0:02                     ` Tejun Heo
2010-01-17 16:26                     ` Ming Lei
2010-01-17 17:18                       ` Eric W. Biederman
2010-01-17 18:03                         ` Dominik Brodowski
2010-01-02 21:49                   ` drm_vm.c:drm_mmap: possible circular locking dependency detected Eric W. Biederman
2010-01-03  0:32                     ` Tejun Heo
2010-01-03  2:06                       ` Eric W. Biederman
2010-01-03  5:01                         ` Tejun Heo
2010-01-03  5:38                           ` Eric W. Biederman
2010-01-03  6:05                             ` Tejun Heo
2010-01-03  7:47                       ` Dmitry Torokhov
2010-01-03 10:57                         ` Eric W. Biederman
2010-01-03 11:14                           ` Eric W. Biederman [this message]
2010-01-04 19:16                             ` Dmitry Torokhov
2010-01-04 18:57                           ` Dmitry Torokhov
2010-01-04 19:43                             ` Eric W. Biederman
2010-01-04 21:12                               ` Dmitry Torokhov
2010-01-04 23:09                               ` Tejun Heo
2009-12-31  8:40           ` drm_vm.c:drm_mmap: possible circular locking dependency detected (was: Re: Linux 2.6.33-rc2 - Merry Christmas ...) Eric W. Biederman

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