linux-kernel - Re: [PATCH] slab: deal with NULL pointers passed to kmem_cache

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:	Wed, 21 Mar 2007 15:45:39 +0100
From:	Jarek Poplawski <jarkao2@...pl>
To:	Pekka J Enberg <penberg@...helsinki.fi>
Cc:	Eric Dumazet <dada1@...mosbay.com>,
	Andrew Morton <akpm@...ux-foundation.org>, mpm@...enic.com,
	Christoph Lameter <clameter@....com>,
	"ast\@domdv\.de" <ast@...dv.de>,
	"linux-kernel\@vger\.kernel\.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] slab: deal with NULL pointers passed to kmem_cache_free

On Wed, Mar 21, 2007 at 03:36:34PM +0200, Pekka J Enberg wrote:
> On Wed, 21 Mar 2007, Jarek Poplawski wrote:
> > With  __kmem_cache_free you would set #1 I hope, but if
> > nobody would use this - debugging time wouldn't change.
> 
> I think you got it backwards. I suggested making the _current_ 
> kmem_cache_free() deal with NULL (so everyone will get it) and add a new 
> optimized __kmem_cache_free() for those call-sites that really need it.

If you could assure optimized version will be used only with
buggy-free code, so you don't waste time for debugging it,
then I really got it backwards, sorry!

> 
> On Wed, 21 Mar 2007, Jarek Poplawski wrote:
> > This could be acceptable, if there were no problems
> > with fixing the errors. But there are problems - bugs
> > like this aren't fixed on time - maybe because people
> > waste too much time per bug?
> 
> You're barking up the wrong tree here, Jarek. I strongly feel that we 
> should be more defensive in the slab for the exact reasons you outlined. 
> There's bunch of bug reports people seem to dismiss as slab errors where 
> in fact it's caused by a buggy caller.

But I can see only one tree here. And I seem to agree with all the rest.
So, I probably really got it backwards...

Must be going to find the right tree,
Jarek P.
-
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/