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From: Andrea Arcangeli <aarcange@redhat.com>
To: Mel Gorman <mel@csn.ul.ie>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Linux-MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Minchan Kim <minchan.kim@gmail.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Christoph Lameter <cl@linux.com>, Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 2/2] mm,migration: Avoid race between shift_arg_pages() and rmap_walk() during migration by not migrating temporary stacks
Date: Thu, 29 Apr 2010 18:21:20 +0200	[thread overview]
Message-ID: <20100429162120.GC22108@random.random> (raw)
In-Reply-To: <1272529930-29505-3-git-send-email-mel@csn.ul.ie>

Hi Mel,

did you see my proposed fix? I'm running with it applied, I'd be
interested if you can test it. Surely it will also work for new
anon-vma code in upstream, because at that point there's just 1
anon-vma and nothing else attached to the vma.

http://git.kernel.org/?p=linux/kernel/git/andrea/aa.git;a=commit;h=6efa1dfa5152ef8d7f26beb188d6877525a9dd03

I think it's wrong to try to handle the race in rmap walk by making
magic checks on vm_flags VM_GROWSDOWN|GROWSUP and
vma->vm_mm->map_count == 1, when we can fix it fully and simply in
exec.c by indexing two vmas in the same anon-vma with a different
vm_start so the pages will be found at all times by the rmap_walk.

WARNING: multiple messages have this Message-ID (diff)
From: Andrea Arcangeli <aarcange@redhat.com>
To: Mel Gorman <mel@csn.ul.ie>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Linux-MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Minchan Kim <minchan.kim@gmail.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Christoph Lameter <cl@linux.com>, Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 2/2] mm,migration: Avoid race between shift_arg_pages() and rmap_walk() during migration by not migrating temporary stacks
Date: Thu, 29 Apr 2010 18:21:20 +0200	[thread overview]
Message-ID: <20100429162120.GC22108@random.random> (raw)
In-Reply-To: <1272529930-29505-3-git-send-email-mel@csn.ul.ie>

Hi Mel,

did you see my proposed fix? I'm running with it applied, I'd be
interested if you can test it. Surely it will also work for new
anon-vma code in upstream, because at that point there's just 1
anon-vma and nothing else attached to the vma.

http://git.kernel.org/?p=linux/kernel/git/andrea/aa.git;a=commit;h=6efa1dfa5152ef8d7f26beb188d6877525a9dd03

I think it's wrong to try to handle the race in rmap walk by making
magic checks on vm_flags VM_GROWSDOWN|GROWSUP and
vma->vm_mm->map_count == 1, when we can fix it fully and simply in
exec.c by indexing two vmas in the same anon-vma with a different
vm_start so the pages will be found at all times by the rmap_walk.

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  reply	other threads:[~2010-04-30 18:24 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-29  8:32 [PATCH 0/2] Fix migration races in rmap_walk() V3 Mel Gorman
2010-04-29  8:32 ` Mel Gorman
2010-04-29  8:32 ` [PATCH 1/2] mm: Take all anon_vma locks in anon_vma_lock Mel Gorman
2010-04-29  8:32   ` Mel Gorman
2010-05-02 17:28   ` Minchan Kim
2010-05-02 17:28     ` Minchan Kim
2010-04-29  8:32 ` [PATCH 2/2] mm,migration: Avoid race between shift_arg_pages() and rmap_walk() during migration by not migrating temporary stacks Mel Gorman
2010-04-29  8:32   ` Mel Gorman
2010-04-29 16:21   ` Andrea Arcangeli [this message]
2010-04-29 16:21     ` Andrea Arcangeli
2010-04-30 19:22     ` Andrea Arcangeli
2010-04-30 19:22       ` Andrea Arcangeli
2010-04-30 20:21       ` Rik van Riel
2010-04-30 20:21         ` Rik van Riel
2010-05-01  9:39       ` Andrea Arcangeli
2010-05-01  9:39         ` Andrea Arcangeli
2010-05-01 13:02         ` Rik van Riel
2010-05-01 13:02           ` Rik van Riel
2010-05-02 17:40     ` Minchan Kim
2010-05-02 17:40       ` Minchan Kim
2010-05-02 18:20       ` Andrea Arcangeli
2010-05-02 18:20         ` Andrea Arcangeli
2010-05-04 10:32     ` Mel Gorman
2010-05-04 10:32       ` Mel Gorman
2010-05-04 12:56       ` Andrea Arcangeli
2010-05-04 12:56         ` Andrea Arcangeli
2010-05-04 14:33         ` Mel Gorman
2010-05-04 14:33           ` Mel Gorman
2010-05-04 14:44           ` Andrea Arcangeli
2010-05-04 14:44             ` Andrea Arcangeli
2010-05-02  1:56   ` Christoph Lameter
2010-05-02  1:56     ` Christoph Lameter
2010-05-04  9:45     ` Mel Gorman
2010-05-04  9:45       ` Mel Gorman
2010-05-10 17:41       ` Christoph Lameter
2010-05-10 17:41         ` Christoph Lameter
2010-05-10 17:56         ` Mel Gorman
2010-05-10 17:56           ` Mel Gorman
2010-05-11 13:59           ` Christoph Lameter
2010-05-11 13:59             ` Christoph Lameter
2010-05-11 15:11             ` Mel Gorman
2010-05-11 15:11               ` Mel Gorman
2010-05-11 15:56               ` Christoph Lameter
2010-05-11 15:56                 ` Christoph Lameter
2010-05-11 16:15                 ` Mel Gorman
2010-05-11 16:15                   ` Mel Gorman
2010-05-11 16:29                   ` Andrea Arcangeli
2010-05-11 16:29                     ` Andrea Arcangeli
2010-05-10 19:05         ` Andrea Arcangeli
2010-05-10 19:05           ` Andrea Arcangeli
2010-05-11  0:10           ` KAMEZAWA Hiroyuki
2010-05-11  0:10             ` KAMEZAWA Hiroyuki
2010-04-30 18:28 ` [PATCH 0/2] Fix migration races in rmap_walk() V3 Andrea Arcangeli
2010-04-30 18:28   ` Andrea Arcangeli
2010-05-01 13:51   ` Johannes Weiner
2010-05-01 13:51     ` Johannes Weiner
2010-05-03 15:33     ` Andrea Arcangeli
2010-05-03 15:33       ` Andrea Arcangeli
2010-05-03 23:41       ` Johannes Weiner
2010-05-03 23:41         ` Johannes Weiner
2010-05-04 17:35         ` Andrea Arcangeli
2010-05-04 17:35           ` Andrea Arcangeli

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