From: Andrew Morton <akpm@linux-foundation.org>
To: Eric Sandeen <sandeen@redhat.com>
Cc: linux-kernel@vger.kernel.org, mhalcrow@us.ibm.com, stable@kernel.org
Subject: Re: [PATCH] eCryptfs - use page_alloc not kmalloc to get a page of memory
Date: Mon, 28 Jul 2008 13:35:04 -0700 [thread overview]
Message-ID: <20080728133504.156f438f.akpm@linux-foundation.org> (raw)
In-Reply-To: <488DF00F.3080809@redhat.com>
On Mon, 28 Jul 2008 11:13:03 -0500
Eric Sandeen <sandeen@redhat.com> wrote:
> With SLUB debugging turned on in 2.6.26, I was getting memory corruption
> when testing eCryptfs. The root cause turned out to be that eCryptfs
> was doing kmalloc(PAGE_CACHE_SIZE); virt_to_page() and treating that
> as a nice page-aligned chunk of memory. But at least with SLUB debugging
> on, this is not always true, and the page we get from virt_to_page does
> not necessarily match the PAGE_CACHE_SIZE worth of memory we got from
> kmalloc.
>
> My simple testcase was 2 loops doing "rm -f fileX; cp /tmp/fileX ." for
> 2 different multi-megabyte files. With this change I no longer see
> the corruption.
The fix applies to both 2.6.25 and to 2.6.26 and appears to be needed
in both kernel versions, so I have tagged it for backporting into both.
next prev parent reply other threads:[~2008-07-28 20:35 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-28 16:13 [PATCH] eCryptfs - use page_alloc not kmalloc to get a page of memory Eric Sandeen
2008-07-28 16:25 ` Michael Halcrow
2008-07-28 16:53 ` Rik van Riel
2008-07-28 20:35 ` Andrew Morton [this message]
2008-07-28 20:38 ` Eric Sandeen
2008-07-28 20:42 ` Pekka Enberg
2008-07-28 21:03 ` Eric Sandeen
2008-07-28 21:12 ` Pekka Enberg
2008-07-30 14:48 ` Christoph Lameter
2008-07-30 14:39 ` Christoph Lameter
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