linux-kernel - Re: [PATCH] kmod: prevent kmod_loop_msg overflow in __request

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Message-ID: <alpine.LNX.2.00.1110041135340.31654@pobox.suse.cz>
Date:	Tue, 4 Oct 2011 11:37:59 +0200 (CEST)
From:	Jiri Kosina <jkosina@...e.cz>
To:	Rusty Russell <rusty@...tcorp.com.au>
Cc:	Andrew Morton <akpm00@...il.com>, linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH] kmod: prevent kmod_loop_msg overflow in
 __request_module()

On Tue, 4 Oct 2011, Rusty Russell wrote:

> > > Well, it will take two billion passes through here to cause the
> > > overflow.  I really hope you found this problem by inspection!
> > 
> > Unfortunately not, it was more painful experience than code reading :)
> 
> Cool!
> 
> Changing it to unsigned would have helped too.  

Still woudln't have helped much in cases of __request_module() being 
called incredibly quickly in an infinite loop. Changing it to unsigned 
will cause the messages being printed in bunches of five, but the effect 
will be the same -- the log being infinitely filled by the printk()s. 
Computers can do infinite loops really quickly today :)

-- 
Jiri Kosina
SUSE Labs
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