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Commit 1d99493b authored by David Woodhouse's avatar David Woodhouse Committed by Linus Torvalds
Browse files

Fix CONFIG_DEBUG_SHIRQ trigger on free_irq() 



Andy Gospodarek pointed out that because we return in the middle of the
free_irq() function, we never actually do call the IRQ handler that just
got deregistered. This should fix it, although I expect Andrew will want
to convert those 'return's to 'break'. That's a separate change though.

Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
Cc: Andy Gospodarek <andy@greyhouse.net>
Cc: Fernando Luis Vzquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f13ef775

kernel/irq/manage.c

+15 −16
Original line number Diff line number Diff line
@@ -405,7 +405,6 @@ void free_irq(unsigned int irq, void *dev_id) 
	struct irq_desc *desc;

	struct irqaction **p;

	unsigned long flags;

	irqreturn_t (*handler)(int, void *) = NULL;



	WARN_ON(in_interrupt());

	if (irq >= NR_IRQS)
@@ -445,28 +444,28 @@ void free_irq(unsigned int irq, void *dev_id) 


			/* Make sure it's not being used on another CPU */

			synchronize_irq(irq);

			if (action->flags & IRQF_SHARED)

				handler = action->handler;

			kfree(action);

			return;

		}

		printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);

		spin_unlock_irqrestore(&desc->lock, flags);

		return;

	}

#ifdef CONFIG_DEBUG_SHIRQ

	if (handler) {

			/*

		 * It's a shared IRQ -- the driver ought to be prepared for it

		 * to happen even now it's being freed, so let's make sure....

		 * We do this after actually deregistering it, to make sure that

		 * a 'real' IRQ doesn't run in parallel with our fake

			 * It's a shared IRQ -- the driver ought to be

			 * prepared for it to happen even now it's

			 * being freed, so let's make sure....  We do

			 * this after actually deregistering it, to

			 * make sure that a 'real' IRQ doesn't run in

			 * parallel with our fake

			 */

			if (action->flags & IRQF_SHARED) {

				local_irq_save(flags);

		handler(irq, dev_id);

				action->handler(irq, dev_id);

				local_irq_restore(flags);

			}

#endif

			kfree(action);

			return;

		}

		printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);

		spin_unlock_irqrestore(&desc->lock, flags);

		return;

	}

}

EXPORT_SYMBOL(free_irq);