linux-kernel - Re: [RFC] [PATCH] cpuset operations causes Badness at mm/slab.c:777 warning

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]

Message-ID: <Pine.LNX.4.64.0706011659170.10164@schroedinger.engr.sgi.com>
Date:	Fri, 1 Jun 2007 17:12:39 -0700 (PDT)
From:	Christoph Lameter <clameter@....com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Jeremy Fitzhardinge <jeremy@...p.org>,
	Srinivasa Ds <srinivasa@...ibm.com>,
	linux-kernel@...r.kernel.org,
	Srivatsa Vaddagiri <vatsa@...ibm.com>,
	Dinakar Guniguntala <dino@...ibm.com>, pj@....com,
	simon.derr@...l.net, clameter@...ulhu.engr.sgi.com,
	rientjes@...gle.com
Subject: Re: [RFC] [PATCH] cpuset operations causes Badness at mm/slab.c:777
 warning

On Fri, 1 Jun 2007, Linus Torvalds wrote:

> > A too large alloc is >32MB or MAX_ORDER << PAGE_SIZE. A BUG_ON in 
> > kmalloc_slab() will trigger.
> 
> Did we use to BUG_ON()? I think that's wrong. There are ways for users to 
> potentially ask the kernel to do big allocations, and the correct response 
> is to say "no can do", not to crash!

There is no way to distinguish that from out of memory. Failing on large 
allocs is what we have always done for kmalloc(). Before 2.6.22 we used to 
fail for allocs > 256k which was a big nuisance for NUMAs large allocs.

The patches in 2.6.22 allow us for the first time to allocate arbitrary 
sized objects up to MAX_ORDER. So we no longer have troubles with large 
NUMA objects.

-
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/