Patch "irqchip/atmel-aic: Fix potential deadlock in ->xlate()" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

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

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
irqchip-atmel-aic-fix-potential-deadlock-in-xlate.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Boris Brezillon <[email protected]>
Date: Tue, 13 Sep 2016 15:58:29 +0200
Subject: irqchip/atmel-aic: Fix potential deadlock in ->xlate()

From: Boris Brezillon <[email protected]>

commit 5eb0d6eb3fac3daa60d9190eed9fa41cf809c756 upstream.

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 irq_gc_{lock_irqsave,unlock_irqrestore}() ones to prevent this bug from happening.

---
 drivers/irqchip/irq-atmel-aic.c  |    5 +++--
 drivers/irqchip/irq-atmel-aic5.c |    5 +++--
 2 files changed, 6 insertions(+), 4 deletions(-)

@@ -176,6 +176,7 @@ static int aic_irq_domain_xlate(struct i
 {
 	struct irq_domain_chip_generic *dgc = d->gc;
 	struct irq_chip_generic *gc;
+	unsigned long flags;
 	unsigned smr;
 	int idx;
 	int ret;

@@ -194,12 +195,12 @@ static int aic_irq_domain_xlate(struct i
 
 	gc = dgc->gc[idx];
 
-	irq_gc_lock(gc);
+	irq_gc_lock_irqsave(gc, flags);
 	smr = irq_reg_readl(gc, AT91_AIC_SMR(*out_hwirq));
 	ret = aic_common_set_priority(intspec[2], &smr);
 	if (!ret)
 		irq_reg_writel(gc, smr, AT91_AIC_SMR(*out_hwirq));
-	irq_gc_unlock(gc);
+	irq_gc_unlock_irqrestore(gc, flags);
 
 	return ret;
 }

@@ -258,6 +258,7 @@ static int aic5_irq_domain_xlate(struct
 				 unsigned int *out_type)
 {
 	struct irq_chip_generic *bgc = irq_get_domain_generic_chip(d, 0);
+	unsigned long flags;
 	unsigned smr;
 	int ret;
 

@@ -269,13 +270,13 @@ static int aic5_irq_domain_xlate(struct
 	if (ret)
 		return ret;
 
-	irq_gc_lock(bgc);
+	irq_gc_lock_irqsave(bgc, flags);
 	irq_reg_writel(bgc, *out_hwirq, AT91_AIC5_SSR);
 	smr = irq_reg_readl(bgc, AT91_AIC5_SMR);
 	ret = aic_common_set_priority(intspec[2], &smr);
 	if (!ret)
 		irq_reg_writel(bgc, intspec[2] | smr, AT91_AIC5_SMR);
-	irq_gc_unlock(bgc);
+	irq_gc_unlock_irqrestore(bgc, flags);
 
 	return ret;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/irqchip-atmel-aic-fix-potential-deadlock-in-xlate.patch queue-4.4/drm-atmel-hlcdc-fix-vertical-scaling.patch queue-4.4/genirq-provide-irq_gc_-lock_irqsave-unlock_irqrestore-helpers.patch