linux-kernel - RE: [PATCH 1/1] mm: prevent poison consumption when splitting THP

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: <SJ1PR11MB608350E5169EE77F86A51E2FFC1BA@SJ1PR11MB6083.namprd11.prod.outlook.com>
Date: Mon, 29 Sep 2025 15:51:46 +0000
From: "Luck, Tony" <tony.luck@...el.com>
To: "Zhuo, Qiuxu" <qiuxu.zhuo@...el.com>, Jiaqi Yan <jiaqiyan@...gle.com>
CC: "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
	"david@...hat.com" <david@...hat.com>, "lorenzo.stoakes@...cle.com"
	<lorenzo.stoakes@...cle.com>, "linmiaohe@...wei.com" <linmiaohe@...wei.com>,
	"ziy@...dia.com" <ziy@...dia.com>, "baolin.wang@...ux.alibaba.com"
	<baolin.wang@...ux.alibaba.com>, "Liam.Howlett@...cle.com"
	<Liam.Howlett@...cle.com>, "npache@...hat.com" <npache@...hat.com>,
	"ryan.roberts@....com" <ryan.roberts@....com>, "dev.jain@....com"
	<dev.jain@....com>, "baohua@...nel.org" <baohua@...nel.org>,
	"nao.horiguchi@...il.com" <nao.horiguchi@...il.com>, "Chen, Farrah"
	<farrah.chen@...el.com>, "linux-mm@...ck.org" <linux-mm@...ck.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "Andrew
 Zaborowski" <andrew.zaborowski@...el.com>
Subject: RE: [PATCH 1/1] mm: prevent poison consumption when splitting THP

> Miaohe mentioned in another e-mail that there was an HWPoisoned flag for the raw error 4K page.
> We could use that flag just to skip that raw error page and still use the zeropage for other
> healthy sub-pages. I'll try that.

That HWPoisoned flag is only set for raw pages where an error has been detected. Maybe Linux
could implement an "is_this_page_all_zero_mc_safe()"[1] that would catch undetected poison and
avoid a crash in that case too?

-Tony

[1] terrible name, pick something better.