From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753034Ab3FYVRT (ORCPT ); Tue, 25 Jun 2013 17:17:19 -0400 Received: from merlin.infradead.org ([205.233.59.134]:59949 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752854Ab3FYVRR (ORCPT ); Tue, 25 Jun 2013 17:17:17 -0400 Date: Tue, 25 Jun 2013 23:17:13 +0200 From: Peter Zijlstra To: David Ahern Cc: Ingo Molnar , LKML Subject: Re: deadlock in scheduler enabling HRTICK feature Message-ID: <20130625211713.GA18796@laptop.programming.kicks-ass.net> References: <51CA0622.8010105@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51CA0622.8010105@gmail.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 25, 2013 at 03:05:38PM -0600, David Ahern wrote: > Peter/Ingo: > > I can reliably cause a deadlock in the scheduler by enabling the HRTICK > feature. I first hit the problem with 2.6.27 but have been able to reproduce > it with newer kernels. I have not tried top of Linus' tree, so perhaps this > has been fixed in 3.10. Yeah, I know.. its been on the todo list forever but its never been important. Its disabled by default and all sched debug features are for those brave enough to keep the pieces ;-)