linux-kernel - Re: [PATCH 0/2] Fix migration races in rmap

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20100426230412.GL8860@random.random>
Date:	Tue, 27 Apr 2010 01:04:12 +0200
From:	Andrea Arcangeli <aarcange@...hat.com>
To:	Mel Gorman <mel@....ul.ie>
Cc:	Linux-MM <linux-mm@...ck.org>, LKML <linux-kernel@...r.kernel.org>,
	Minchan Kim <minchan.kim@...il.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Christoph Lameter <cl@...ux.com>,
	Rik van Riel <riel@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 0/2] Fix migration races in rmap_walk()

On Mon, Apr 26, 2010 at 11:37:56PM +0100, Mel Gorman wrote:
> The other issues raised about expand_downwards will need to be re-examined to
> see if they still exist and transparent hugepage support will need further
> thinking to see if split_huge_page() can deal with these situations.

So patch 1 is for aa.git too, and patch 2 is only for mainline with
the new anon-vma changes (patch 2 not needed in current aa.git, and if
I apply it, it'll deadlock so...) right?

split_huge_page is somewhat simpler and more strict in its checking
than migrate.c in this respect, and yes patch 2 will also need to be
extended to cover split_huge_page the moment I stop backing out the
new anon-vma code (but it won't be any different, whatever works for
migrate will also work for split_huge_page later).

For now I'm much more interested in patch 1 and I'll leave patch 2 to
mainline digestion and check it later hope to find all issues fixed by
the time transparent hugepage gets merged.

About patch 1 it's very interesting because I looked at the race
against fork and migrate yesterday and I didn't see issues but I'm
going to read your patch 1 in detail now to understand what is the
problem you're fixing.

Good you posted this fast, so I can try to help ;)
Andrea
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/