From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753067Ab1LSNkW (ORCPT ); Mon, 19 Dec 2011 08:40:22 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60760 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752622Ab1LSNkR (ORCPT ); Mon, 19 Dec 2011 08:40:17 -0500 Date: Mon, 19 Dec 2011 08:40:12 -0500 From: Vivek Goyal To: Nate Custer Cc: Jens Axboe , Avi Kivity , Marcelo Tosatti , kvm@vger.kernel.org, linux-kernel Subject: Re: [RFT PATCH] blkio: alloc per cpu data from worker thread context( Re: kvm deadlock) Message-ID: <20111219134012.GA7175@redhat.com> References: <54FC5923-2123-4BDD-A506-EA57DCE0C1F6@cpanel.net> <20111214122511.GD18317@amt.cnet> <4EE8A7ED.7060703@redhat.com> <4EE8C8EA.9070207@kernel.dk> <20111215194712.GA11194@redhat.com> <20111216202907.GH7586@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Dec 18, 2011 at 03:25:48PM -0600, Nate Custer wrote: > > On Dec 16, 2011, at 2:29 PM, Vivek Goyal wrote: > > Thanks for testing it Nate. I did some debugging and found out that patch > > is doing double free on per cpu pointer hence the crash you are running > > into. I could reproduce this problem on my box. It is just a matter of > > doing rmdir on the blkio cgroup. > > > > I understood the cmpxchg() semantics wrong. I have fixed it now and > > no crashes on directory removal. Can you please give this version a > > try. > > > > Thanks > > Vivek > > After 24 hours of stress testing the machine remains up and working without issue. I will continue to test it, but am reasonably confident that this patch resolves my issue. That's good to know. While you continue to stress test, I will make some minor modifications to the patch. (Thinking of delaying the retry of allocation of per cpu memory in case previous attempts failed). Thanks Vivek