linux-kernel - Re: [PATCH 1/3] HWPOISON, hugetlbfs: fix warning on freeing hwpoisoned hugepage

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:	Thu,  6 Dec 2012 21:18:14 -0500
From:	Naoya Horiguchi <n-horiguchi@...jp.nec.com>
To:	Tony Luck <tony.luck@...el.com>
Cc:	Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Andi Kleen <andi.kleen@...el.com>,
	Wu Fengguang <fengguang.wu@...el.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH 1/3] HWPOISON, hugetlbfs: fix warning on freeing hwpoisoned hugepage

On Wed, Dec 05, 2012 at 10:13:42PM +0000, Luck, Tony wrote:
> > This patch fixes the warning from __list_del_entry() which is triggered
> > when a process tries to do free_huge_page() for a hwpoisoned hugepage.
> 
> Ultimately it would be nice to avoid poisoning huge pages. Generally we know the
> location of the poison to a cache line granularity (but sometimes only to a 4K
> granularity) ... and it is rather inefficient to take an entire 2M page out of service.
> With 1G pages things would be even worse!!

Thanks for the comment.
And yes, it's remaining work to be done.

> It also makes life harder for applications that would like to catch the SIGBUS
> and try to take their own recovery actions. Losing more data than they really
> need to will make it less likely that they can do something to work around the
> loss.
> 
> Has anyone looked at how hard it might be to have the code in memory-failure.c
> break up a huge page and only poison the 4K that needs to be taken out of service?

This work is one of my interest and became a bit easier than used to be,
because now transparent hugepage works commonly and some of code can be
copied from or shared with it.

Thanks,
Naoya
--
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/