From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756151AbcIMM5u (ORCPT ); Tue, 13 Sep 2016 08:57:50 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:58651 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755189AbcIMM5s (ORCPT ); Tue, 13 Sep 2016 08:57:48 -0400 Date: Tue, 13 Sep 2016 14:55:20 +0200 (CEST) From: Thomas Gleixner To: Boris Brezillon 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() In-Reply-To: <1473761409-16226-1-git-send-email-boris.brezillon@free-electrons.com> Message-ID: References: <1473761409-16226-1-git-send-email-boris.brezillon@free-electrons.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Thanks, tglx