From: Andrew Morton <akpm@linux-foundation.org>
To: Jonathan Corbet <corbet@lwn.net>
Cc: Mel Gorman <mel@csn.ul.ie>,
Andrea Arcangeli <aarcange@redhat.com>,
Christoph Lameter <cl@linux-foundation.org>,
Adam Litke <agl@us.ibm.com>, Avi Kivity <avi@redhat.com>,
David Rientjes <rientjes@google.com>,
Minchan Kim <minchan.kim@gmail.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Rik van Riel <riel@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 07/11] Memory compaction core
Date: Wed, 24 Mar 2010 14:14:00 -0700 [thread overview]
Message-ID: <20100324141400.72479ce6.akpm@linux-foundation.org> (raw)
In-Reply-To: <20100324145946.372f3f31@bike.lwn.net>
On Wed, 24 Mar 2010 14:59:46 -0600
Jonathan Corbet <corbet@lwn.net> wrote:
> On Wed, 24 Mar 2010 13:33:47 -0700
> Andrew Morton <akpm@linux-foundation.org> wrote:
>
> > > + VM_BUG_ON(cc == NULL);
> >
> > It's a bit strange to test this when we're about to oops anyway. The
> > oops will tell us the same thing.
>
> ...except that we've seen a fair number of null pointer dereference
> exploits that have told us something altogether different. Are we
> *sure* we don't want to test for null pointers...?
>
It's hard to see what the test gains us really - the kernel has
zillions of pointer derefs, any of which could be NULL if we have a
bug. Are we more likely to have a bug here than elsewhere?
This one will oops on a plain old read, so it's a bit moot in this
case.
--
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next prev parent reply other threads:[~2010-03-24 21:15 UTC|newest]
Thread overview: 85+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-23 12:25 [PATCH 0/11] Memory Compaction v5 Mel Gorman
2010-03-23 12:25 ` [PATCH 01/11] mm,migration: Take a reference to the anon_vma before migrating Mel Gorman
2010-03-23 12:25 ` [PATCH 02/11] mm,migration: Do not try to migrate unmapped anonymous pages Mel Gorman
2010-03-23 17:22 ` Christoph Lameter
2010-03-23 18:04 ` Mel Gorman
2010-03-23 12:25 ` [PATCH 03/11] mm: Share the anon_vma ref counts between KSM and page migration Mel Gorman
2010-03-23 17:25 ` Christoph Lameter
2010-03-23 23:55 ` KAMEZAWA Hiroyuki
2010-03-23 12:25 ` [PATCH 04/11] Allow CONFIG_MIGRATION to be set without CONFIG_NUMA or memory hot-remove Mel Gorman
2010-03-23 12:25 ` [PATCH 05/11] Export unusable free space index via /proc/unusable_index Mel Gorman
2010-03-23 17:31 ` Christoph Lameter
2010-03-23 18:14 ` Mel Gorman
2010-03-24 0:03 ` KAMEZAWA Hiroyuki
2010-03-24 0:16 ` Minchan Kim
2010-03-24 0:13 ` KAMEZAWA Hiroyuki
2010-03-24 10:25 ` Mel Gorman
2010-03-23 12:25 ` [PATCH 06/11] Export fragmentation index via /proc/extfrag_index Mel Gorman
2010-03-23 17:37 ` Christoph Lameter
2010-03-23 12:25 ` [PATCH 07/11] Memory compaction core Mel Gorman
2010-03-23 17:56 ` Christoph Lameter
2010-03-23 18:15 ` Mel Gorman
2010-03-23 18:33 ` Christoph Lameter
2010-03-23 18:58 ` Mel Gorman
2010-03-23 19:20 ` Christoph Lameter
2010-03-24 1:03 ` KAMEZAWA Hiroyuki
2010-03-24 1:47 ` Minchan Kim
2010-03-24 1:53 ` KAMEZAWA Hiroyuki
2010-03-24 2:10 ` Minchan Kim
2010-03-24 10:57 ` Mel Gorman
2010-03-24 20:33 ` Andrew Morton
2010-03-24 20:59 ` Jonathan Corbet
2010-03-24 21:14 ` Andrew Morton [this message]
2010-03-24 21:19 ` Christoph Lameter
2010-03-24 21:19 ` Andrea Arcangeli
2010-03-24 21:28 ` Jonathan Corbet
2010-03-24 21:47 ` Andrea Arcangeli
2010-03-24 21:54 ` Jonathan Corbet
2010-03-24 22:06 ` Andrea Arcangeli
2010-03-24 21:57 ` Andrea Arcangeli
2010-03-25 9:13 ` Mel Gorman
2010-03-23 12:25 ` [PATCH 08/11] Add /proc trigger for memory compaction Mel Gorman
2010-03-23 18:25 ` Christoph Lameter
2010-03-23 18:32 ` Mel Gorman
2010-03-24 20:33 ` Andrew Morton
2010-03-26 10:46 ` Mel Gorman
2010-03-23 12:25 ` [PATCH 09/11] Add /sys trigger for per-node " Mel Gorman
2010-03-23 18:27 ` Christoph Lameter
2010-03-23 22:45 ` Minchan Kim
2010-03-24 0:19 ` KAMEZAWA Hiroyuki
2010-03-23 12:25 ` [PATCH 10/11] Direct compact when a high-order allocation fails Mel Gorman
2010-03-23 23:10 ` Minchan Kim
2010-03-24 11:11 ` Mel Gorman
2010-03-24 11:59 ` Minchan Kim
2010-03-24 12:06 ` Minchan Kim
2010-03-24 12:10 ` Mel Gorman
2010-03-24 12:09 ` Mel Gorman
2010-03-24 12:25 ` Minchan Kim
2010-03-24 1:19 ` KAMEZAWA Hiroyuki
2010-03-24 11:40 ` Mel Gorman
2010-03-25 0:30 ` KAMEZAWA Hiroyuki
2010-03-25 9:48 ` Mel Gorman
2010-03-25 9:50 ` KAMEZAWA Hiroyuki
2010-03-25 10:16 ` Mel Gorman
2010-03-26 1:03 ` KAMEZAWA Hiroyuki
2010-03-26 9:40 ` Mel Gorman
2010-03-24 20:48 ` Andrew Morton
2010-03-25 0:57 ` KAMEZAWA Hiroyuki
2010-03-25 10:21 ` Mel Gorman
2010-03-23 12:25 ` [PATCH 11/11] Do not compact within a preferred zone after a compaction failure Mel Gorman
2010-03-23 18:31 ` Christoph Lameter
2010-03-23 18:39 ` Mel Gorman
2010-03-23 19:27 ` Christoph Lameter
2010-03-24 10:37 ` Mel Gorman
2010-03-24 19:54 ` Christoph Lameter
2010-03-24 20:53 ` Andrew Morton
2010-03-25 9:40 ` Mel Gorman
-- strict thread matches above, loose matches on Subject: below --
2010-03-12 16:41 [PATCH 0/11] Memory Compaction v4 Mel Gorman
2010-03-12 16:41 ` [PATCH 07/11] Memory compaction core Mel Gorman
2010-03-15 13:44 ` Minchan Kim
2010-03-15 14:41 ` Mel Gorman
2010-03-17 10:31 ` KOSAKI Motohiro
2010-03-17 11:40 ` Mel Gorman
2010-03-18 2:35 ` KOSAKI Motohiro
2010-03-18 11:43 ` Mel Gorman
2010-03-19 6:21 ` KOSAKI Motohiro
2010-03-18 17:08 ` Mel Gorman
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