From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934620AbbI2Kij (ORCPT ); Tue, 29 Sep 2015 06:38:39 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:46100 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934030AbbI2Kic (ORCPT ); Tue, 29 Sep 2015 06:38:32 -0400 Date: Tue, 29 Sep 2015 12:32:37 +0200 From: Peter Zijlstra To: mingo@kernel.org Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, fweisbec@gmail.com, oleg@redhat.com, umgwanakikbuti@gmail.com, tglx@linutronix.de, rostedt@goodmis.org Subject: Re: [RFC][PATCH 12/11] sched: Add preempt_count invariant check Message-ID: <20150929103237.GA7520@twins.programming.kicks-ass.net> References: <20150929092825.540553633@infradead.org> <20150929102755.GD3816@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150929102755.GD3816@twins.programming.kicks-ass.net> 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, Sep 29, 2015 at 12:27:55PM +0200, Peter Zijlstra wrote: > > Ingo requested I keep my debug check for the preempt_count invariant. > > Requested-by: Ingo Molnar > Signed-off-by: Peter Zijlstra (Intel) > --- > kernel/sched/core.c | 5 +++++ > 1 file changed, 5 insertions(+) > > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -2503,6 +2503,11 @@ static struct rq *finish_task_switch(str > struct mm_struct *mm = rq->prev_mm; > long prev_state; > > + if (unlikely(WARN_ONCE(preempt_count() != 2, That should have: s/2/2*PREEMPT_DISABLE_OFFSET/ or something, otherwise !PREEMPT_COUNT kernels will go funny. > + "corrupted preempt_count: %s/%d/0x%x\n", > + current->comm, current->pid, preempt_count()))) > + preempt_count_set(INIT_PREEMPT_COUNT); > + > rq->prev_mm = NULL; > > /*