[GIT PULL] irq fix

From: Ingo Molnar
Date: Fri Jan 08 2016 - 07:42:47 EST


Linus,

Please pull the latest irq-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git irq-urgent-for-linus

# HEAD: abc7e40c81d113ef4bacb556f0a77ca63ac81d85 genirq: Prevent chip buslock deadlock

Fixes a core IRQ subsystem deadlock.

Thanks,

Ingo

------------------>
Thomas Gleixner (1):
genirq: Prevent chip buslock deadlock


kernel/irq/manage.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 0eebaeef317b..6ead200370da 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1434,6 +1434,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
if (!desc)
return NULL;

+ chip_bus_lock(desc);
raw_spin_lock_irqsave(&desc->lock, flags);

/*
@@ -1447,7 +1448,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
if (!action) {
WARN(1, "Trying to free already-free IRQ %d\n", irq);
raw_spin_unlock_irqrestore(&desc->lock, flags);
-
+ chip_bus_sync_unlock(desc);
return NULL;
}

@@ -1475,6 +1476,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
#endif

raw_spin_unlock_irqrestore(&desc->lock, flags);
+ chip_bus_sync_unlock(desc);

unregister_handler_proc(irq, action);

@@ -1553,9 +1555,7 @@ void free_irq(unsigned int irq, void *dev_id)
desc->affinity_notify = NULL;
#endif

- chip_bus_lock(desc);
kfree(__free_irq(irq, dev_id));
- chip_bus_sync_unlock(desc);
}
EXPORT_SYMBOL(free_irq);