linux-kernel - Re: pktcdvd oops

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]

Date:	Wed, 7 Nov 2007 23:06:47 +0100 (CET)
From:	Peter Osterlund <petero2@...ia.com>
To:	Tejun Heo <htejun@...il.com>
cc:	Thomas Maier <balagi@...tmail.de>,
	Jens Axboe <jens.axboe@...cle.com>,
	linux-kernel <linux-kernel@...r.kernel.org>, gregkh@...e.de
Subject: Re: pktcdvd oops

On Wed, 7 Nov 2007, Tejun Heo wrote:

> Peter Osterlund wrote:
>> If the
>> __module_get() is not safe because the module code could have already
>> been unloaded, how can it possibly be made safe by adding more code to
>> the pktcdvd module? If the module is unloaded, trying to execute its
>> code can't be a good thing no matter what the code does.
>
> sysfs itself is now out of module lifespan rules.  sysfs callbacks are
> guaranteed to stay in memory while running by sysfs node removal waiting
> for completion of in-flight operations before returning.  In pktcdvd's
> case, class_destroy() call in pkt_sysfs_cleanup() will wait for all
> in-flight sysfs r/w ops to complete.
>
> So, even while sysfs callbacks are executing, the module beneath can die
> but it will stay in memory till all the callbacks return.  You need to
> test module liveness using try_module_get() (and it can fail) if you
> want to grab module reference from sysfs callbacks.

Thanks for the explanation.

Given that explanation, I think the patch is correct and it does fix the 
BUG on my computer. Can you please push it upstream?

In any case:

Acked-by: Peter Osterlund <petero2@...ia.com>

-- 
Peter Osterlund - petero2@...ia.com
http://web.telia.com/~u89404340
-
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/