From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754727AbcIMNBI (ORCPT ); Tue, 13 Sep 2016 09:01:08 -0400 Received: from down.free-electrons.com ([37.187.137.238]:36024 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750951AbcIMNBH (ORCPT ); Tue, 13 Sep 2016 09:01:07 -0400 Date: Tue, 13 Sep 2016 15:00:54 +0200 From: Boris Brezillon To: Thomas Gleixner Cc: Jason Cooper , Marc Zyngier , Nicolas Ferre , Jean-Christophe Plagniol-Villard , Alexandre Belloni , linux-kernel@vger.kernel.org, stable@kernel.vger.org Subject: Re: [PATCH] irqchip/atmel-aic: Fix potential deadlock in ->xlate() Message-ID: <20160913150054.0297a114@bbrezillon> In-Reply-To: References: <1473761409-16226-1-git-send-email-boris.brezillon@free-electrons.com> Organization: Free Electrons X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 13 Sep 2016 14:55:20 +0200 (CEST) Thomas Gleixner wrote: > On Tue, 13 Sep 2016, Boris Brezillon wrote: > > > aic5_irq_domain_xlate() and aic_irq_domain_xlate() take the generic chip > > lock without disabling interrupts, which can lead to a deadlock if an > > interrupt occurs while the lock is held in one of these functions. > > > > Replace irq_gc_{lock,unlock}() calls by > > raw_spin_{lock_irqsave,unlock_irqrestore}() ones to prevent this bug from > > happening. > > > > Signed-off-by: Boris Brezillon > > Fixes: b1479ebb7720 ("irqchip: atmel-aic: Add atmel AIC/AIC5 drivers") > > Cc: > > --- > > drivers/irqchip/irq-atmel-aic.c | 5 +++-- > > drivers/irqchip/irq-atmel-aic5.c | 5 +++-- > > 2 files changed, 6 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/irqchip/irq-atmel-aic.c b/drivers/irqchip/irq-atmel-aic.c > > index 112e17c2768b..447a8b0f1395 100644 > > --- a/drivers/irqchip/irq-atmel-aic.c > > +++ b/drivers/irqchip/irq-atmel-aic.c > > @@ -176,6 +176,7 @@ static int aic_irq_domain_xlate(struct irq_domain *d, > > { > > struct irq_domain_chip_generic *dgc = d->gc; > > struct irq_chip_generic *gc; > > + unsigned long flags; > > unsigned smr; > > int idx; > > int ret; > > @@ -194,11 +195,11 @@ static int aic_irq_domain_xlate(struct irq_domain *d, > > > > gc = dgc->gc[idx]; > > > > - irq_gc_lock(gc); > > + raw_spin_lock_irqsave(&gc->lock, flags); > > Please provide a primitive, i.e. irq_gc_lock_irqsave(), for it. Sure, but that means flagging this patch for stable as well. Are you okay with that? > > Thanks, > > tglx