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Fix crash with irqpoll due to the IRQF_IRQPOLL flag testing

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With irqpoll enabled, trying to test the IRQF_IRQPOLL flag in the
actions would cause a NULL pointer dereference if no action was
installed (for example, the driver might have been unloaded with
interrupts still pending).

So be a bit more careful about testing the flag by making sure to test
for that case.

(The actual _change_ is trivial, the patch is more than a one-liner
because I rewrote the testing to also be much more readable.

Original (discarded) bugfix by Bernhard Walle.

Cc: Bernhard Walle <bwalle@suse.de>
Tested-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2007-05-24 08:37:14 -07:00
parent db2668fdbe
commit 92ea77275b
1 changed files with 37 additions and 9 deletions
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46
kernel/irq/spurious.c
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@ -135,6 +135,39 @@ report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
}
}
static inline int try_misrouted_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
{
struct irqaction *action;
if (!irqfixup)
return 0;
/* We didn't actually handle the IRQ - see if it was misrouted? */
if (action_ret == IRQ_NONE)
return 1;
/*
* But for 'irqfixup == 2' we also do it for handled interrupts if
* they are marked as IRQF_IRQPOLL (or for irq zero, which is the
* traditional PC timer interrupt.. Legacy)
*/
if (irqfixup < 2)
return 0;
if (!irq)
return 1;
/*
* Since we don't get the descriptor lock, "action" can
* change under us. We don't really care, but we don't
* want to follow a NULL pointer. So tell the compiler to
* just load it once by using a barrier.
*/
action = desc->action;
barrier();
return action && (action->flags & IRQF_IRQPOLL);
}
void note_interrupt(unsigned int irq, struct irq_desc *desc,
irqreturn_t action_ret)
{
@ -144,15 +177,10 @@ void note_interrupt(unsigned int irq, struct irq_desc *desc,
report_bad_irq(irq, desc, action_ret);
}
if (unlikely(irqfixup)) {
/* Don't punish working computers */
if ((irqfixup == 2 && ((irq == 0) ||
(desc->action->flags & IRQF_IRQPOLL))) ||
action_ret == IRQ_NONE) {
int ok = misrouted_irq(irq);
if (action_ret == IRQ_NONE)
desc->irqs_unhandled -= ok;
}
if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
int ok = misrouted_irq(irq);
if (action_ret == IRQ_NONE)
desc->irqs_unhandled -= ok;
}
desc->irq_count++;