Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=92ea77275b5345c1300433f28689493dc4163f24
Commit: 92ea77275b5345c1300433f28689493dc4163f24
Parent: db2668fdbeb2e3c95ebadf95856c9e31a8a8d569
Author: Linus Torvalds <[EMAIL PROTECTED]>
AuthorDate: Thu May 24 08:37:14 2007 -0700
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Thu May 24 08:37:14 2007 -0700
Fix crash with irqpoll due to the IRQF_IRQPOLL flag testing
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 <[EMAIL PROTECTED]>
Tested-by: Vivek Goyal <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
kernel/irq/spurious.c | 46 +++++++++++++++++++++++++++++++++++++---------
1 files changed, 37 insertions(+), 9 deletions(-)
diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c
index b0d81aa..bd9e272 100644
--- a/kernel/irq/spurious.c
+++ b/kernel/irq/spurious.c
@@ -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++;
-
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