linux-kernel - Re: [PATCH v3 4/4] memory-hotplug: fix pages missed by race rather than failng

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]

Date:	Fri, 07 Sep 2012 09:48:51 +0900
From:	Kamezawa Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To:	Minchan Kim <minchan@...nel.org>
CC:	Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, Mel Gorman <mgorman@...e.de>,
	Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>,
	Xishi Qiu <qiuxishi@...wei.com>,
	Wen Congyang <wency@...fujitsu.com>
Subject: Re: [PATCH v3 4/4] memory-hotplug: fix pages missed by race rather
 than failng

(2012/09/07 9:39), Minchan Kim wrote:
> If race between allocation and isolation in memory-hotplug offline
> happens, some pages could be in MIGRATE_MOVABLE of free_list although
> the pageblock's migratetype of the page is MIGRATE_ISOLATE.
> 
> The race could be detected by get_freepage_migratetype
> in __test_page_isolated_in_pageblock. If it is detected, now EBUSY
> gets bubbled all the way up and the hotplug operations fails.
> 
> But better idea is instead of returning and failing memory-hotremove,
> move the free page to the correct list at the time it is detected.
> It could enhance memory-hotremove operation success ratio although
> the race is really rare.
> 
> Suggested-by: Mel Gorman <mgorman@...e.de>
> Signed-off-by: Minchan Kim <minchan@...nel.org>

Sounds reasonable. Thank you very much !

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>


--
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/