Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932206AbdIGPLG (ORCPT ); Thu, 7 Sep 2017 11:11:06 -0400 Received: from merlin.infradead.org ([205.233.59.134]:43644 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753819AbdIGPLF (ORCPT ); Thu, 7 Sep 2017 11:11:05 -0400 Message-Id: <20170907150614.094206976@infradead.org> User-Agent: quilt/0.63-1 Date: Thu, 07 Sep 2017 17:03:52 +0200 From: Peter Zijlstra To: mingo@kernel.org, tglx@linutronix.de Cc: linux-kernel@vger.kernel.org, peterz@infradead.org Subject: [PATCH 3/4] sched: WARN when migrating to an offline CPU References: <20170907150349.063852465@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=peterz-sched-warn-migrate-to-offline.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 609 Lines: 21 Migrating tasks to offline CPUs is a pretty big fail, warn about it. Signed-off-by: Peter Zijlstra (Intel) --- kernel/sched/core.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1173,6 +1173,10 @@ void set_task_cpu(struct task_struct *p, WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || lockdep_is_held(&task_rq(p)->lock))); #endif + /* + * Clearly, migrating tasks to offline CPUs is a fairly daft thing. + */ + WARN_ON_ONCE(!cpu_online(new_cpu)); #endif trace_sched_migrate_task(p, new_cpu);