netdev - Re: netlink circular locking dependency

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4857BBB6.6010709@trash.net>
Date:	Tue, 17 Jun 2008 15:27:18 +0200
From:	Patrick McHardy <kaber@...sh.net>
To:	Jarek Poplawski <jarkao2@...il.com>
CC:	Marcel Holtmann <marcel@...tmann.org>, netdev@...r.kernel.org,
	Ingo Molnar <mingo@...e.hu>, Thomas Graf <tgraf@...g.ch>
Subject: Re: netlink circular locking dependency

Jarek Poplawski wrote:
> On Tue, Jun 17, 2008 at 03:07:44PM +0200, Patrick McHardy wrote:
>> Jarek Poplawski wrote:
>>> On Tue, Jun 17, 2008 at 02:50:19PM +0200, Patrick McHardy wrote:
>>> ...
>>>> Thanks for testing. Unfortunately the module unload races look
>>>> more complicated to fix and I'm busy with other things, so it
>>>> would great if someone else could fix this.
>>> Patrick, I wonder if simply adding an additional mutex e.g.
>>> genl_lock_table() around all the rest (after your patch) genl_locks
>>> could be enough until some major rework. This should prevent any
>>> new races and there are no lockups, I guess?
>> Not sure I understand you correctly, where exactly would
>> this mutex be taken?
> 
> Around (before) each genl_lock(), so any change would need these two
> locks. genl_lock() alone would work like read lock (plus cb change).
> But, I can miss something... Of course, it's meant as a temporary
> solution, until Thomas does it right.

I guess that might work. But simply using module references to
prevent the module from going away while the mutex is not held
doesn't appear to be more complicated.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html