From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752099AbbAFXU2 (ORCPT ); Tue, 6 Jan 2015 18:20:28 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:55456 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750753AbbAFXU1 (ORCPT ); Tue, 6 Jan 2015 18:20:27 -0500 Date: Wed, 7 Jan 2015 00:20:25 +0100 From: Pavel Machek To: One Thousand Gnomes Cc: Mark Seaborn , kernel list , luto@amacapital.net Subject: Re: DRAM unreliable under specific access patern Message-ID: <20150106232025.GA32569@amd> References: <20141224220818.GA17655@amd> <20150105192329.5f32c155@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150105192329.5f32c155@lxorguk.ukuu.org.uk> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 2015-01-05 19:23:29, One Thousand Gnomes wrote: > > In the meantime, I created test that actually uses physical memory, > > 8MB apart, as described in some footnote. It is attached. It should > > work, but it needs boot with specific config options and specific > > kernel parameters. > > Why not just use hugepages. You know the alignment guarantees for 1GB > pages and that means you don't even need to be root > > In fact - should we be disabling 1GB huge page support by default at this > point, at least on non ECC boxes ? Actually, I could not get my test code to run; and as code from https://github.com/mseaborn/rowhammer-test reproduces issue for me, I stopped trying. I could not get it to damage memory of other process than itself (but that should be possible), I guess that's next thing to try. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html