Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753267AbaBQOug (ORCPT ); Mon, 17 Feb 2014 09:50:36 -0500 Received: from merlin.infradead.org ([205.233.59.134]:43617 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750830AbaBQOue (ORCPT ); Mon, 17 Feb 2014 09:50:34 -0500 Date: Mon, 17 Feb 2014 15:50:27 +0100 From: Peter Zijlstra To: Boris Ostrovsky Cc: mingo@redhat.com, linux-kernel@vger.kernel.org, konrad.wilk@oracle.com, juri.lelli@gmail.com Subject: Re: [PATCH] sched/deadline: Test for CPU's presence explicitly Message-ID: <20140217145027.GU27965@twins.programming.kicks-ass.net> References: <1392646353-1874-1-git-send-email-boris.ostrovsky@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1392646353-1874-1-git-send-email-boris.ostrovsky@oracle.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 Mon, Feb 17, 2014 at 09:12:33AM -0500, Boris Ostrovsky wrote: > A hot-removed CPU may have ID that is numerically larger than the number of > existing CPUs in the system (e.g. we can unplug CPU 4 from a system that > has CPUs 0, 1 and 4). > > Thus the WARN_ONs should check whether the CPU in question is currently > present, not whether its ID value is less than num_present_cpus(). > > Reported-by: Konrad Rzeszutek Wilk > Signed-off-by: Boris Ostrovsky Thanks!, please also always CC the author of the code in question. > --- > kernel/sched/cpudeadline.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c > index 045fc74..5b8838b 100644 > --- a/kernel/sched/cpudeadline.c > +++ b/kernel/sched/cpudeadline.c > @@ -70,7 +70,7 @@ static void cpudl_heapify(struct cpudl *cp, int idx) > > static void cpudl_change_key(struct cpudl *cp, int idx, u64 new_dl) > { > - WARN_ON(idx > num_present_cpus() || idx == IDX_INVALID); > + WARN_ON(!cpu_present(idx) || idx == IDX_INVALID); > > if (dl_time_before(new_dl, cp->elements[idx].dl)) { > cp->elements[idx].dl = new_dl; > @@ -117,7 +117,7 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p, > } > > out: > - WARN_ON(best_cpu > num_present_cpus() && best_cpu != -1); > + WARN_ON(!cpu_present(best_cpu) && best_cpu != -1); > > return best_cpu; > } > @@ -137,7 +137,7 @@ void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid) > int old_idx, new_cpu; > unsigned long flags; > > - WARN_ON(cpu > num_present_cpus()); > + WARN_ON(!cpu_present(cpu)); > > raw_spin_lock_irqsave(&cp->lock, flags); > old_idx = cp->cpu_to_idx[cpu]; > -- > 1.8.1.4 > -- 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/