handle_IRQ_event either enables IRQs or leaves them disabled for the
entire chain. However, there is nothing in request_irq or setup_irq
which ensures that all IRQs in a chain will have the same
IRQF_DISABLED.
This seems like a bug to me. Below are two possible fixes -
enable/disable IRQs for each action or refuse to register an IRQ if
there is a mismatched IRQF_DISABLED.
--
Work email - jdike at linux dot intel dot com
Refuse to register an IRQ if it has a mismatched IRQF_DISABLED with
what's already in the IRQ chain.
Signed-off-by: Jeff Dike <[email protected]>
--
kernel/irq/manage.c | 8 ++++++++
1 file changed, 8 insertions(+)
Index: linux-2.6.21-mm/kernel/irq/manage.c
===================================================================
--- linux-2.6.21-mm.orig/kernel/irq/manage.c 2007-05-23 09:01:16.000000000 -0400
+++ linux-2.6.21-mm/kernel/irq/manage.c 2007-05-23 09:02:28.000000000 -0400
@@ -301,6 +301,14 @@ int setup_irq(unsigned int irq, struct i
goto mismatch;
}
+ /*
+ * Handlers must agree on disabling IRQs since
+ * handle_IRQ_event leaves IRQs either on or off for
+ * the entire chain.
+ */
+ if ((old->flags ^ new->flags) & IRQF_DISABLED)
+ goto mismatch;
+
#if defined(CONFIG_IRQ_PER_CPU)
/* All handlers must agree on per-cpuness */
if ((old->flags & IRQF_PERCPU) !=
Move the enabling/disabling of IRQs into the loop so that actions with
differing IRQF_DISABLED get the IRQ enabling that they asked for.
Signed-off-by: Jeff Dike <[email protected]>
--
kernel/irq/handle.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
Index: linux-2.6.21-mm/kernel/irq/handle.c
===================================================================
--- linux-2.6.21-mm.orig/kernel/irq/handle.c 2007-05-16 18:21:18.000000000 -0400
+++ linux-2.6.21-mm/kernel/irq/handle.c 2007-05-23 09:02:57.000000000 -0400
@@ -133,20 +133,21 @@ irqreturn_t handle_IRQ_event(unsigned in
handle_dynamic_tick(action);
- if (!(action->flags & IRQF_DISABLED))
- local_irq_enable_in_hardirq();
-
do {
+ if (!(action->flags & IRQF_DISABLED))
+ local_irq_enable_in_hardirq();
+
ret = action->handler(irq, action->dev_id);
if (ret == IRQ_HANDLED)
status |= action->flags;
retval |= ret;
action = action->next;
+
+ local_irq_disable();
} while (action);
if (status & IRQF_SAMPLE_RANDOM)
add_interrupt_randomness(irq);
- local_irq_disable();
return retval;
}
-
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