linux-kernel - Re: [RFC][PATCH 0/3] configfs: Make nested default groups lockdep-friendly

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:	Tue, 20 May 2008 19:08:54 +0200
From:	Louis Rilling <Louis.Rilling@...labs.com>
To:	Arjan van de Ven <arjan@...radead.org>
CC:	Joel.Becker@...cle.com, linux-kernel@...r.kernel.org,
	ocfs2-devel@....oracle.com
Subject: Re: [RFC][PATCH 0/3] configfs: Make nested default groups lockdep-friendly

Arjan van de Ven a écrit :
> On Tue, 20 May 2008 18:33:20 +0200
> Louis Rilling <Louis.Rilling@...labs.com> wrote:
> 
>> Hi all,
>>
>> The following patches fix lockdep warnings resulting from (correct)
>> recursive locking in configfs.
>>
>> Current lockdep annotations for inode mutexes in configfs are
>> lockdep-friendly provided that:
>> 1/ config_groups have at most one level of default groups (see
>>    configfs_attach_group()),
>> 2/ config_groups having default groups are never removed (see
>>    configfs_detach_prep()).
>>
>> Since lockdep does not handle such correct recursion, the idea is to
>> insert lockdep_off()/lockdep_on() for inode mutexes as soon as the
>> level of recursion of the I_MUTEX_PARENT -> I_MUTEX_CHILD dependency
>> pattern increases.
> 
> I'm... not entirely happy with such a solution ;(
> 
> there must be a better one.

Hmm, to me there are three solutions:

1/ keep lockdep and configfs like they are, and use this patchset

2/ enhance lockdep to handle wariable-depth but correct recursion:
seems uncertain...


3/ remove this recursive locking from configfs:
unfortunately, it seems that there are a good reasons for doing
recursive inode locking, at least when removing a config_group with
default groups. So, seems uncertain too...

Other ideas?

-- 
Dr Louis Rilling			Kerlabs
Skype: louis.rilling			Batiment Germanium
Phone: (+33|0) 6 80 89 08 23		80 avenue des Buttes de Coesmes
http://www.kerlabs.com/			35700 Rennes
--
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/