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genirq: Prevent potential NULL dereference in irq_set_irq_wake()

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In kernel/irq/manage.c::irq_set_irq_wake() we call
irq_get_desc_buslock() which may return NULL, but the code
dereferences the result unconditionally.

irq_set_irq_wake() has lots of callers - I checked a few and I couldn't
find anything that guarantees that they won't call it with some input that
will cause irq_get_desc_buslock() to return NULL, so I think it's a good
thing to test and -EINVAL was the most sane error code in this situation
that I could think of.

Not all callers test the return value of irq_set_irq_wake(), but those
that do take != 0 to mean error as far as I can see, so they should be
fine. I guess those that don't test actually should, but that's a
different issue.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1106092300360.17868@swampdragon.chaosbits.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Jesper Juhl 2011-06-09 23:14:58 +02:00 committed by Thomas Gleixner
parent 7f45e5cd17
commit 13863a66c9
1 changed files with 3 additions and 0 deletions
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3
kernel/irq/manage.c
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@ -491,6 +491,9 @@ int irq_set_irq_wake(unsigned int irq, unsigned int on)
struct irq_desc *desc = irq_get_desc_buslock(irq, &flags);
int ret = 0;
if (!desc)
return -EINVAL;
/* wakeup-capable irqs can be shared between drivers that
* don't need to have the same sleep mode behaviors.
*/