From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752942AbdI1LEM (ORCPT ); Thu, 28 Sep 2017 07:04:12 -0400 Received: from omzsmtpe03.verizonbusiness.com ([199.249.25.208]:40442 "EHLO omzsmtpe03.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752543AbdI1LEK (ORCPT ); Thu, 28 Sep 2017 07:04:10 -0400 From: "Levin, Alexander (Sasha Levin)" X-Host: ranger.odc.vzwcorp.com To: Peter Zijlstra CC: Sasha Levin , Ingo Molnar , Thomas Gleixner , "linux-kernel@vger.kernel.org List" Subject: Re: [PATCH 3/4] sched: WARN when migrating to an offline CPU Thread-Topic: [PATCH 3/4] sched: WARN when migrating to an offline CPU Thread-Index: AQHTOElfM9+kG7jFU0Ct/E9UJTo0QQ== Date: Thu, 28 Sep 2017 11:03:10 +0000 Message-ID: <20170928110308.lvpxf5fw7crbwsg6@sasha-lappy> References: <20170907150349.063852465@infradead.org> <20170907150614.094206976@infradead.org> <20170928103541.2adtamm7koi4k5zh@hirez.programming.kicks-ass.net> In-Reply-To: <20170928103541.2adtamm7koi4k5zh@hirez.programming.kicks-ass.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: NeoMutt/20170113 (1.7.2) x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="us-ascii" Content-ID: <80D8761B6E3FED429A01D88B82823E8C@vzwcorp.com> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v8SB4Gn9013673 On Thu, Sep 28, 2017 at 12:35:41PM +0200, Peter Zijlstra wrote: >On Thu, Sep 28, 2017 at 02:14:15AM -0700, Sasha Levin wrote: >> On Thu, Sep 7, 2017 at 8:03 AM, Peter Zijlstra wrote: >> > Migrating tasks to offline CPUs is a pretty big fail, warn about it. >> >> Hey Peter, >> >> This seems to get hit on the latest -next: >> >> [2035565360.446794] Unregister pv shared memory for cpu 2 >> [2035565360.467930] numa_remove_cpu cpu 2 node 2: mask now 6 >> [2035565360.471431] ------------[ cut here ]------------ >> [2035565360.472548] WARNING: CPU: 2 PID: 24 at > kernel/sched/core.c:1178 set_task_cpu (kernel/sched/core.c:1157) >> [2035565360.473840] Modules linked in: >> [2035565360.474632] CPU: 2 PID: 24 Comm: migration/2 Not tainted > 4.14.0-rc2-next-20170927+ #252 > >Urgh, weird. That really shouldn't happen. Can you easily reproduce? Looks like yes. Seems like it's enough to stress CPU hotplug + trinity. If you have patches you want me try send them my way. -- Thanks, Sasha