Look up the descriptor and check that it is found in handle_one_irq
before checking if we are on the irq stack, and call the handler
directly using the descriptor if we are on the stack.
We need check irq_to_desc finds the descriptor to avoid a NULL
pointer dereference. It could have failed because the number from
ppc_md.get_irq was above NR_IRQS, or various exceptional conditions
with sparse irqs (eg race conditions while freeing an irq if its was
not shutdown in the controller).
fe12bc2c99 (genirq: Uninline and sanity check generic_handle_irq())
moved generic_handle_irq out of line to allow its use by interrupt
controllers in modules. However, handle_one_irq is core arch code.
It already knows the details of struct irq_desc and handling irqs in
the nested irq case. This will avoid the extra stack frame to return
the value we don't check.
Signed-off-by: Milton Miller <milt...@bga.com>
Index: work.git/arch/powerpc/kernel/irq.c
===================================================================
--- work.git.orig/arch/powerpc/kernel/irq.c 2011-05-21 01:06:49.042239939
-0500
+++ work.git/arch/powerpc/kernel/irq.c 2011-05-21 02:00:41.912586798 -0500
@@ -295,17 +295,20 @@ static inline void handle_one_irq(unsign
unsigned long saved_sp_limit;
struct irq_desc *desc;
+ desc = irq_to_desc(irq);
+ if (!desc)
+ return;
+
/* Switch to the irq stack to handle this */
curtp = current_thread_info();
irqtp = hardirq_ctx[smp_processor_id()];
if (curtp == irqtp) {
/* We're already on the irq stack, just handle it */
- generic_handle_irq(irq);
+ desc->handle_irq(irq, desc);
return;
}
- desc = irq_to_desc(irq);
saved_sp_limit = current->thread.ksp_limit;
irqtp->task = curtp->task;
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