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genirq: Protect access to irq_desc->action in can_request_irq()

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can_request_irq() accesses and dereferences irq_desc->action w/o
holding irq_desc->lock. So action can be freed on another CPU before
it's dereferenced. Unlikely, but ...

Protect it with desc->lock.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2010-03-23 22:40:53 +01:00
parent 0b1adaa031
commit cc8c3b7843
1 changed files with 4 additions and 0 deletions
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4
kernel/irq/manage.c
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@ -382,6 +382,7 @@ int can_request_irq(unsigned int irq, unsigned long irqflags)
{
struct irq_desc *desc = irq_to_desc(irq);
struct irqaction *action;
unsigned long flags;
if (!desc)
return 0;
@ -389,11 +390,14 @@ int can_request_irq(unsigned int irq, unsigned long irqflags)
if (desc->status & IRQ_NOREQUEST)
return 0;
raw_spin_lock_irqsave(&desc->lock, flags);
action = desc->action;
if (action)
if (irqflags & action->flags & IRQF_SHARED)
action = NULL;
raw_spin_unlock_irqrestore(&desc->lock, flags);
return !action;
}