From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Cooper Subject: Re: [PATCH v2 00/26] genirq: fix use of irq_find_mapping outside of legal RCU context Date: Wed, 3 Sep 2014 08:37:29 -0400 Message-ID: <20140903123729.GM30467@titan.lakedaemon.net> References: <1409047421-27649-1-git-send-email-marc.zyngier@arm.com> <87y4uap98n.fsf@approximate.cambridge.arm.com> <20140903120406.GK30467@titan.lakedaemon.net> <540707B3.4050305@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mho-02-ewr.mailhop.org ([204.13.248.72]:51793 "EHLO mho-02-ewr.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932267AbaICMiU (ORCPT ); Wed, 3 Sep 2014 08:38:20 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Thomas Gleixner Cc: Marc Zyngier , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-omap@vger.kernel.org" , "linux@arm.linux.org.uk" , "shawn.guo@freescale.com" , "kernel@pengutronix.de" , "tony@atomide.com" , Catalin Marinas , Will Deacon , "jonas@southpole.se" , "shc_work@mail.ru" , "baohua@kernel.org" , "maxime.ripard@free-electrons.com" , "khilman@linaro.org" , "sboyd@codeaurora.org" , Lorenzo Pieralisi , "larry.bassel@linaro.org" On Wed, Sep 03, 2014 at 02:25:09PM +0200, Thomas Gleixner wrote: > On Wed, 3 Sep 2014, Marc Zyngier wrote: > > [Dropping linux@openrisc.net from the CC list] > > > > On 03/09/14 13:09, Thomas Gleixner wrote: > > > On Wed, 3 Sep 2014, Jason Cooper wrote: > > > > > >> On Wed, Aug 27, 2014 at 10:33:44AM +0100, Marc Zyngier wrote: > > >>> Hi Thomas, > > >>> > > >>> On Tue, Aug 26 2014 at 10:34:51 pm BST, Thomas Gleixner wrote: > > >>>> On Tue, 26 Aug 2014, Marc Zyngier wrote: > > >>>> > > >>>>> A number of irqchip drivers are directly calling irq_find_mapping, > > >>>>> which may use a rcu_read_lock call when walking the radix tree. > > >>>>> > > >>>>> Turns out that if you hit that point with CONFIG_PROVE_RCU enabled, > > >>>>> the kernel will shout at you, as using RCU in this context may be > > >>>>> illegal (specially if coming from the idle state, where RCU would be > > >>>>> in a quiescent state). > > >>>>> > > >>>>> A possible fix would be to wrap calls to irq_find_mapping into a > > >>>>> RCU_NONIDLE macro, but that really looks ugly. > > >>>>> > > >>>>> This patch series introduce another generic IRQ entry point > > >>>>> (handle_domain_irq), which has the exact same behaviour as handle_IRQ > > >>>>> (as defined on arm, arm64 and openrisc), except that it also takes a > > >>>>> irq_domain pointer. This allows the logical IRQ lookup to be done > > >>>>> inside the irq_{enter,exit} section, which contains a > > >>>>> rcu_irq_{enter,exit}, making it safe. > > >>>> > > >>>> Looks good. Should this be routed to the genirq tree? > > >>> > > >>> I'm happy for you to take this series, provided the architecture > > >>> maintainers agree on it (I'm still to hear from the openrisc guys, and > > >>> their mailing-list seems to positively hate my guts). > > >> > > >> I think everyone's had a chance to look over it by now. Thomas, shall I > > >> take the series? > > > > > > Yes please. > > > > Do you want a pull request? Or are you picking up the patches from the ML? > > Did you pick up the Acked/Reviewed/Ignored-by tags? Marc, unless you've already done it, I'll pull from the ml, since I need to apply the Acked-bys and tweak the subject lines. thx, Jason.