linux-kernel - Re: [PATCH v2] mm: check_new_page_bad() directly returns in __PG

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: <20160518140337.GG2527@techsingularity.net>
Date:	Wed, 18 May 2016 15:03:37 +0100
From:	Mel Gorman <mgorman@...hsingularity.net>
To:	Naoya Horiguchi <n-horiguchi@...jp.nec.com>
Cc:	Vlastimil Babka <vbabka@...e.cz>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Naoya Horiguchi <nao.horiguchi@...il.com>
Subject: Re: [PATCH v2] mm: check_new_page_bad() directly returns in
 __PG_HWPOISON case

On Wed, May 18, 2016 at 10:09:50AM +0000, Naoya Horiguchi wrote:
> From c600b1ee6c36b3df6973f5365b4179c92f3c08e3 Mon Sep 17 00:00:00 2001
> From: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
> Date: Wed, 18 May 2016 18:42:57 +0900
> Subject: [PATCH v2] mm: check_new_page_bad() directly returns in __PG_HWPOISON
>  case
> 
> Currently we check page->flags twice for "HWPoisoned" case of
> check_new_page_bad(), which can cause a race with unpoisoning.
> This race unnecessarily taints kernel with "BUG: Bad page state".
> check_new_page_bad() is the only caller of bad_page() which is interested
> in __PG_HWPOISON, so let's move the hwpoison related code in bad_page()
> to it.
> 
> Signed-off-by: Naoya Horiguchi <n-horiguchi@...jp.nec.com>

Acked-by: Mel Gorman <mgorman@...hsingularity.net>

-- 
Mel Gorman
SUSE Labs