Re: [Bug #13112] Oops in drain_array

From: Christoph Lameter <cl@linux.com>
To: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: David Rientjes <rientjes@google.com>, Bart <mmx@riz.pl>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Kernel Testers List <kernel-testers@vger.kernel.org>,
	"Rafael J. Wysocki" <rjw@sisk.pl>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [Bug #13112] Oops in drain_array
Date: Mon, 27 Apr 2009 10:04:47 -0400 (EDT)	[thread overview]
Message-ID: <alpine.DEB.1.10.0904271000200.16119@qirst.com> (raw)
In-Reply-To: <84144f020904270152o6567e84cj914934120315bf90@mail.gmail.com>

On Mon, 27 Apr 2009, Pekka Enberg wrote:

>   18:   4a 8b 8c eb 68 01 00    mov    0x168(%rbx,%r13,8),%rcx # l3 =
> cachep->nodelists[node];
>   1f:   00
>   20:   48 8b 16                mov    (%rsi),%rdx
>   23:   48 8b 46 08             mov    0x8(%rsi),%rax
>   27:   48 89 42 08             mov    %rax,0x8(%rdx)
>   2b:*  48 89 10                mov    %rdx,(%rax)     <-- trapping instruction
>   2e:   89 e8                   mov    %ebp,%eax
>   30:   48 c7 06 00 01 10 00    movq   $0x100100,(%rsi)
>   37:   48 c7 46 08 00 02 20    movq   $0x200200,0x8(%rsi)
>
> it seems like list_del() in free_block() explodes because because
> ->prev ("rax") of slab->list is bogus ("0000000000000cd0").

Where do I find the rest of the information regarding this report?
bugzilla does only contain a pointer to the initial report on lkml no
discussion.

Typically these oopses occur because the slab header at the beginning of a
slab is overwritten. Enable debugging. Switching to SLUB would give better
diagnostics.