From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753597Ab2ITSNF (ORCPT ); Thu, 20 Sep 2012 14:13:05 -0400 Received: from mail.skyhub.de ([78.46.96.112]:49469 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753333Ab2ITSNC (ORCPT ); Thu, 20 Sep 2012 14:13:02 -0400 Date: Thu, 20 Sep 2012 20:12:58 +0200 From: Borislav Petkov To: Tejun Heo Cc: Michael Wang , Peter Zijlstra , Akinobu Mita , lkml Subject: Re: kernel BUG at kernel/sched/core.c:1465! Message-ID: <20120920181258.GA17181@liondog.tnic> Mail-Followup-To: Borislav Petkov , Tejun Heo , Michael Wang , Peter Zijlstra , Akinobu Mita , lkml References: <20120919091230.GA25576@liondog.tnic> <505AB9F7.6030605@linux.vnet.ibm.com> <20120920125801.GA15045@x1.osrc.amd.com> <20120920171045.GC28934@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20120920171045.GC28934@google.com> 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 Thu, Sep 20, 2012 at 10:10:45AM -0700, Tejun Heo wrote: > Yeah, it's powernow-k8 migrating kworker to a different CPU. It's > really curious that there are multiple reports of this in this cycle. > Nothing on workqueue side has changed and powernow-k8 has been > broken for very long time. The only way this can get triggered is by > contending on fidvid_mutex in powernow-k8. I suppose something changed > in such way that this happens with some regularity. Have no specific > idea what. Anyways, mainline should be okay now. Yep, it is. I'm running with it for a couple of hours already and no issues. Btw, we'd normally investigate why powernow-k8 b0rkage appears now but after the next merge window, that functionality is moving to acpi-cpufreq so powernow-k8 should really be only for K8s then. We'll see how that whole thing pans out as late as 3.7-rc cycle. Thanks. -- Regards/Gruss, Boris.