Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755637AbaDGTtd (ORCPT ); Mon, 7 Apr 2014 15:49:33 -0400 Received: from smtp1.ngi.it ([88.149.128.112]:37266 "EHLO smtp1.ngi.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755384AbaDGTt2 (ORCPT ); Mon, 7 Apr 2014 15:49:28 -0400 Message-ID: <5343015C.5090309@katamail.com> Date: Mon, 07 Apr 2014 21:49:48 +0200 From: Michele Ballabio User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Peter Zijlstra CC: linux-kernel@vger.kernel.org, toralf.foerster@gmx.de, fweisbec@gmail.com, mingo@kernel.org, Steven Rostedt Subject: Re: Bisected KVM hang on x86-32 between v3.12 and v3.13 References: <5341707F.5000406@katamail.com> <20140407150337.GO10526@twins.programming.kicks-ass.net> <20140407150705.GB13658@twins.programming.kicks-ass.net> In-Reply-To: <20140407150705.GB13658@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/04/2014 17:07, Peter Zijlstra wrote: > On Mon, Apr 07, 2014 at 05:03:37PM +0200, Peter Zijlstra wrote: >> So what I suspect at this point is that because i386 and x86_64 have a >> difference in current_thread_info() (i386 is stack based), we end up >> setting the TIF_NEED_RESCHED bit on the wrong stack. >> >> Now I have some vague memories of propagating the TIF flags on stack >> switch, but I cannot remember what arch we did that for. Let me stare at >> this a little more. >> >> Also, IFF this is the case, then the fingered patch above (and your >> suggested 'fix') aren't the real curlpit/cure but simply make it >> more/less likely to happen. Understood. >> Now, Steve had a patch somewhere that would make i386 use per-cpu >> variables for current_thread_info() just like x86_64 already does I >> think. Let me go find them too. > > Ohh, goodie, they're already in Linus' tree. Could you see if current > git still suffers this problem? It is fixed on current -master (3.14.0-10773-gb8780c3). Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/