linux-kernel - Re: [PATCH v2] mm: compaction: fix special case -1 order checks

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] [day] [month] [year] [list]

Date:	Thu, 2 Jun 2011 11:38:20 +0100
From:	Mel Gorman <mgorman@...e.de>
To:	Michal Hocko <mhocko@...e.cz>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Minchan Kim <minchan.kim@...il.com>, linux-mm@...ck.org,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] mm: compaction: fix special case -1 order checks

On Mon, May 30, 2011 at 05:24:50PM +0200, Michal Hocko wrote:
> <SNIP>
> mm: compaction: fix special case -1 order checks
> 
> 56de7263 (mm: compaction: direct compact when a high-order allocation
> fails) introduced a check for cc->order == -1 in compact_finished. We
> should continue compacting in that case because the request came from
> userspace and there is no particular order to compact for.
> Similar check has been added by 82478fb7 (mm: compaction:
> prevent division-by-zero during user-requested compaction) for
> compaction_suitable.
> 
> The check is, however, done after zone_watermark_ok which uses order as
> a right hand argument for shifts. Not only watermark check is pointless
> if we can break out without it but it also uses 1 << -1 which is not
> well defined (at least from C standard). Let's move the -1 check above
> zone_watermark_ok.
> 
> [Minchan Kim <minchan.kim@...il.com> - caught compaction_suitable]
> Signed-off-by: Michal Hocko <mhocko@...e.cz>
> Cc: Mel Gorman <mgorman@...e.de>

Acked-by: Mel Gorman <mgorman@...e.de>

-- 
Mel Gorman
SUSE Labs
--
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/