[PATCH v3 2/2] irqchip/atmel-aic: Fix potential deadlock in ->xlate()

Boris Brezillon
2016-09-13T13:58:41Z

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@vger.kernel.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
---
Changes in v3:
- introduce and use the irq_gc_{lock_irqsave,unlock_irqrestore}() helpers

Changes in v2:
- add Marc's ack
- fix stable ML address

fixup! irqchip/atmel-aic: Fix potential deadlock in ->xlate()
---
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..37f952dd9fc9 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);
+ irq_gc_lock_irqsave(gc, 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);
+ irq_gc_unlock_irqrestore(gc, flags);

return ret;
}
diff --git a/drivers/irqchip/irq-atmel-aic5.c b/drivers/irqchip/irq-atmel-aic5.c
index 4f0d068e1abe..2a624d87a035 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);
+ irq_gc_lock_irqsave(bgc, 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);
+ irq_gc_unlock_irqrestore(bgc, flags);

return ret;
}
--
2.7.4