From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751380AbdJCRUS (ORCPT ); Tue, 3 Oct 2017 13:20:18 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:51990 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751090AbdJCRUR (ORCPT ); Tue, 3 Oct 2017 13:20:17 -0400 Date: Tue, 3 Oct 2017 18:18:47 +0100 From: Mark Rutland To: Marc Zyngier Cc: Lorenzo Pieralisi , Suzuki K Poulose , Pawel Moll , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 0/2] bus: CCN/CCI: Fix use of smp_processor_id() Message-ID: <20171003171847.GG4931@leverpostej> References: <20171003171413.18592-1-marc.zyngier@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171003171413.18592-1-marc.zyngier@arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 03, 2017 at 06:14:11PM +0100, Marc Zyngier wrote: > I've just noticed that both the CCI and CCN drivers have a small > buglet in that they call smp_processor_id() from preemptible context, > which is frown upon (having just booted a 4.13 kernel with > DEBUG_PREEMPT on my Seattle, I was surprised to be greeted with a nice > backtrace...). > > I've tested the CCN patch on the same Seatle box, but I've only > compile-tested the equivalent CCI patch (which is obviously correct -- > famous last words...). > > Thanks, > > M. > > * From v1: Keep the current CPU refcount until we have registered the > CPU notifiers, making sure we don't race against a surprise hotplug > off. > > Marc Zyngier (2): > bus: arm-ccn: Fix use of smp_processor_id() in preemptible context > bus: arm-cci: Fix use of smp_processor_id() in preemptible context For both: Acked-by: Mark Rutland Thanks, Mark.