Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933073AbbELNUN (ORCPT ); Tue, 12 May 2015 09:20:13 -0400 Received: from e33.co.us.ibm.com ([32.97.110.151]:51224 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932975AbbELNUK (ORCPT ); Tue, 12 May 2015 09:20:10 -0400 Date: Tue, 12 May 2015 06:20:04 -0700 From: "Paul E. McKenney" To: Peter Zijlstra Cc: Chris Metcalf , Gilad Ben Yossef , Steven Rostedt , Ingo Molnar , Andrew Morton , Rik van Riel , Tejun Heo , Thomas Gleixner , Frederic Weisbecker , Christoph Lameter , "Srivatsa S. Bhat" , linux-doc@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/6] nohz: support PR_DATAPLANE_STRICT mode Message-ID: <20150512132004.GL6776@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <1431107927-13998-1-git-send-email-cmetcalf@ezchip.com> <1431107927-13998-6-git-send-email-cmetcalf@ezchip.com> <20150512093858.GI21418@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150512093858.GI21418@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15051213-0009-0000-0000-00000AC1A185 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1374 Lines: 37 On Tue, May 12, 2015 at 11:38:58AM +0200, Peter Zijlstra wrote: > On Fri, May 08, 2015 at 01:58:46PM -0400, Chris Metcalf wrote: > > +++ b/kernel/time/tick-sched.c > > @@ -436,6 +436,20 @@ static void dataplane_quiesce(void) > > (jiffies - start)); > > dump_stack(); > > } > > + > > + /* > > + * Kill the process if it violates STRICT mode. Note that this > > + * code also results in killing the task if a kernel bug causes an > > + * irq to be delivered to this core. > > + */ > > + if ((task->dataplane_flags & (PR_DATAPLANE_STRICT|PR_DATAPLANE_PRCTL)) > > + == PR_DATAPLANE_STRICT) { > > + pr_warn("Dataplane STRICT mode violated; process killed.\n"); > > + dump_stack(); > > + task->dataplane_flags &= ~PR_DATAPLANE_QUIESCE; > > + local_irq_enable(); > > + do_group_exit(SIGKILL); > > + } > > } > > So while I'm all for hard fails like this, can we not provide a wee bit > more information in the siginfo ? And maybe use a slightly less fatal > signal, such that userspace can actually catch it and dump state in > debug modes? Agreed, a bit more debug state would be helpful. Thanx, Paul -- 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/