linux-kernel - Re: [RFC/PATCH] SLQB: Mark the allocator as broken PowerPC and S390

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:	Thu, 17 Sep 2009 20:28:42 +0200
From:	Nick Piggin <npiggin@...e.de>
To:	Mel Gorman <mel@....ul.ie>
Cc:	Pekka Enberg <penberg@...helsinki.fi>,
	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	cl@...ux-foundation.org, heiko.carstens@...ibm.com, mingo@...e.hu,
	sachinp@...ibm.com
Subject: Re: [RFC/PATCH] SLQB: Mark the allocator as broken PowerPC and S390

On Thu, Sep 17, 2009 at 07:18:32PM +0100, Mel Gorman wrote:
> > Ahh... it's pretty lame of me. Sachin has been a willing tester :(
> > I have spent quite a few hours looking at it but I never found
> > many good leads. Much appreciated if you can make more progress on
> > it.
> 
> Nothing much so far. I've reproduced the problem based on 2.6.31 and slqb-core
> from Pekka's tree but not a whole pile else. I don't know SLQB at all so the
> investigation is fuzzy. It appears to initialise SLQB ok but crashes later when
> setting up SCSI. Not 100% sure what the triggering event is but it might be
> userspace starting up and other CPUs get involved, possibly corrupting lists.
> 
> This machine has two CPUs (0, 1) and two nodes with actual memory (2,3).
> After applying a patch to kmem_cache_create, I see in the console
> 
> MEL::Creating cache pgd_cache CPU 0 Node 0
> MEL::Creating cache pmd_cache CPU 0 Node 0
> MEL::Creating cache pid_namespace CPU 0 Node 0
> MEL::Creating cache shmem_inode_cache CPU 0 Node 0
> MEL::Creating cache scsi_data_buffer CPU 1 Node 0
> 
> It crashes at this point during creation before the struct kmem_cache has
> been allocated from kmem_cache_cache. Note it's kmem_cache_cache we are
> failing to allocate from, not scsi_data_buffer.

Yes, it's crashing in kmem_cache_create, when trying to allocate from
kmem_cache_cache.

I didn't get much further. I had thought something must be NULL or
not set up correctly in kmem_cache_cache, but I didn't work out what.

If you can identify the precondition which cases the crash (or even
just have a static counter of the number of caches created, to trigger
at the crashing cache create), then perhaps you can dump some more
details of the kmem_cache_cache.

Thanks,
Nick
--
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/