linux-kernel - Re: [PATCH] Mark the correct zone as full when scanning zonelists

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: <20080911144155.c70ef145.akpm@linux-foundation.org>
Date:	Thu, 11 Sep 2008 14:41:55 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Mel Gorman <mel@....ul.ie>
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	kamezawa.hiroyu@...fujitsu.com, apw@...dowen.org
Subject: Re: [PATCH] Mark the correct zone as full when scanning zonelists

On Thu, 11 Sep 2008 22:25:51 +0100
Mel Gorman <mel@....ul.ie> wrote:

> The for_each_zone_zonelist() uses a struct zoneref *z cursor when scanning
> zonelists to keep track of where in the zonelist it is. The zoneref that
> is returned corresponds to the the next zone that is to be scanned, not
> the current one as it originally thought of as an opaque list.
> 
> When the page allocator is scanning a zonelist, it marks zones that it
> temporarily full zones to eliminate near-future scanning attempts.

That sentence needs help.

> It uses
> the zoneref for the marking and consequently the incorrect zone gets marked
> full. This leads to a suitable zone being skipped in the mistaken belief
> it is full. This patch corrects the problem by changing zoneref to be the
> current zone being scanned instead of the next one.

Applicable to 2.6.26 as well, yes?


Someone reported a bug a few weeks ago which I think this patch will fix,
yes?  I don't remember who that was, nor do I recall the precise details
of what the userspace-visible (mis)behaviour was.

Are you able to fill in the gaps here?  Put yourself in the position of
a poor little -stable maintainer scratching his head wondering ytf he
was sent this patch.

Thanks.
--
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/