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[PATCH] irqchip/atmel-aic: Fix potential deadlock in ->xlate()

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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 <boris.brezillon@free-electrons.com>
Fixes: b1479ebb7720 ("irqchip: atmel-aic: Add atmel AIC/AIC5 drivers")
Cc: <stable@kernel.vger.org>
---
 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);
 	smr = irq_reg_readl(gc, AT91_AIC_SMR(*out_hwirq));
 	aic_common_set_priority(intspec[2], &smr);
 	irq_reg_writel(gc, smr, AT91_AIC_SMR(*out_hwirq));
-	irq_gc_unlock(gc);
+	raw_spin_unlock_irqrestore(&gc->lock, flags);
 
 	return ret;
 }
diff --git a/drivers/irqchip/irq-atmel-aic5.c b/drivers/irqchip/irq-atmel-aic5.c
index 4f0d068e1abe..8c024107fd03 100644
--- a/drivers/irqchip/irq-atmel-aic5.c
+++ b/drivers/irqchip/irq-atmel-aic5.c
@@ -258,6 +258,7 @@ static int aic5_irq_domain_xlate(struct irq_domain *d,
 				 unsigned int *out_type)
 {
 	struct irq_chip_generic *bgc = irq_get_domain_generic_chip(d, 0);
+	unsigned long flags;
 	unsigned smr;
 	int ret;
 
@@ -269,12 +270,12 @@ static int aic5_irq_domain_xlate(struct irq_domain *d,
 	if (ret)
 		return ret;
 
-	irq_gc_lock(bgc);
+	raw_spin_lock_irqsave(&bgc->lock, flags);
 	irq_reg_writel(bgc, *out_hwirq, AT91_AIC5_SSR);
 	smr = irq_reg_readl(bgc, AT91_AIC5_SMR);
 	aic_common_set_priority(intspec[2], &smr);
 	irq_reg_writel(bgc, smr, AT91_AIC5_SMR);
-	irq_gc_unlock(bgc);
+	raw_spin_unlock_irqrestore(&bgc->lock, flags);
 
 	return ret;
 }
-- 
2.7.4

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[PATCH] irqchip/atmel-aic: Fix potential deadlock in ->xlate() Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-09-13 12:20 +0200
  Re: [PATCH] irqchip/atmel-aic: Fix potential deadlock in ->xlate() Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-09-13 12:20 +0200
  Re: [PATCH] irqchip/atmel-aic: Fix potential deadlock in ->xlate() Marc Zyngier <marc.zyngier@arm.com> - 2016-09-13 12:30 +0200
  Re: [PATCH] irqchip/atmel-aic: Fix potential deadlock in ->xlate() Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-09-13 13:30 +0200
    Re: [PATCH] irqchip/atmel-aic: Fix potential deadlock in ->xlate() Marc Zyngier <marc.zyngier@arm.com> - 2016-09-13 14:30 +0200
  Re: [PATCH] irqchip/atmel-aic: Fix potential deadlock in ->xlate() Thomas Gleixner <tglx@linutronix.de> - 2016-09-13 15:00 +0200
    Re: [PATCH] irqchip/atmel-aic: Fix potential deadlock in ->xlate() Boris Brezillon <boris.brezillon@free-electrons.com> - 2016-09-13 15:10 +0200
      Re: [PATCH] irqchip/atmel-aic: Fix potential deadlock in ->xlate() Thomas Gleixner <tglx@linutronix.de> - 2016-09-13 15:20 +0200

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