From: Glauber Costa <glommer@parallels.com>
To: Christoph Lameter <cl@linux.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>,
David Rientjes <rientjes@google.com>,
linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
linux-mm@kvack.org, Pekka Enberg <penberg@cs.helsinki.fi>
Subject: Re: [PATCH] slab+slob: dup name string
Date: Wed, 23 May 2012 19:01:52 +0400 [thread overview]
Message-ID: <4FBCFBE0.2080803@parallels.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1205230947490.30940@router.home>
On 05/23/2012 06:48 PM, Christoph Lameter wrote:
> On Wed, 23 May 2012, James Bottomley wrote:
>
>>>> So, why not simply patch slab to rely on the string lifetime being the
>>>> cache lifetime (or beyond) and therefore not having it take a copy?
>
> Well thats they way it was for a long time. There must be some reason that
> someone started to add this copying business.... Pekka?
>
From git:
commit 84c1cf62465e2fb0a692620dcfeb52323ab03d48
Author: Pekka Enberg <penberg@kernel.org>
Date: Tue Sep 14 23:21:12 2010 +0300
SLUB: Fix merged slab cache names
As explained by Linus "I'm Proud to be an American" Torvalds:
Looking at the merging code, I actually think it's totally
buggy. If you have something like this:
- load module A: create slab cache A
- load module B: create slab cache B that can merge with A
- unload module A
- "cat /proc/slabinfo": BOOM. Oops.
exactly because the name is not handled correctly, and you'll have
module B holding open a slab cache that has a name pointer that points
to module A that no longer exists.
So if I understand it correctly, this is mostly because the name string
outlives the cache in the slub case, because of merging ?
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next prev parent reply other threads:[~2012-05-23 15:03 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-21 15:18 Glauber Costa
2012-05-21 15:35 ` Christoph Lameter
2012-05-22 3:22 ` David Rientjes
2012-05-22 7:23 ` Glauber Costa
2012-05-22 9:45 ` Glauber Costa
2012-05-22 13:56 ` Christoph Lameter
2012-05-22 15:19 ` Glauber Costa
2012-05-22 17:16 ` Christoph Lameter
2012-05-22 22:31 ` David Rientjes
2012-05-23 11:46 ` James Bottomley
2012-05-23 12:08 ` Glauber Costa
2012-05-23 12:24 ` James Bottomley
2012-05-23 14:48 ` Christoph Lameter
2012-05-23 14:50 ` Glauber Costa
2012-05-24 0:18 ` Dave Chinner
2012-05-24 12:06 ` Glauber Costa
2012-05-23 15:01 ` Glauber Costa [this message]
2012-05-23 15:17 ` Christoph Lameter
2012-05-23 15:15 ` Glauber Costa
2012-05-23 13:48 ` Christoph Lameter
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