linux-kernel - Re: kernel 3.0: BUG: soft lockup: find_get

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: <20111031163422.GC3466@redhat.com>
Date:	Mon, 31 Oct 2011 17:34:22 +0100
From:	Andrea Arcangeli <aarcange@...hat.com>
To:	Nai Xia <nai.xia@...il.com>
Cc:	Mel Gorman <mgorman@...e.de>, Hugh Dickins <hughd@...gle.com>,
	Pawel Sikora <pluto@...k.net>,
	Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
	jpiszcz@...idpixels.com, arekm@...-linux.org,
	linux-kernel@...r.kernel.org
Subject: Re: kernel 3.0: BUG: soft lockup: find_get_pages+0x51/0x110

Hi Nai,

On Sat, Oct 22, 2011 at 01:07:11PM +0800, Nai Xia wrote:
> Yeah, anon_vma root lock is a big lock. And JFYI, actually I am doing 
> some very nasty hacking on anon_vma and one of the side effects is 
> breaking the root lock into pieces. But this area is pretty 
> convolved by many racing conditions. I hope some day I will finally make
> my patch work and have your precious review of it. :-)

:) It's going to be not trivial, initially it was not a shared lock
but it wasn't safe that way (especially with migrate required a
reliable rmap_walk) and using a shared lock across all
same_anon_vma/same_vma lists was the only way to be safe and solve the
races.
--
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/