genirq: assert that irq handlers are indeed running in hardirq context

Make sure the genirq layer handlers are indeed running handlers
in hardirq context. That is the genirq expectation and doing
anything else is broken.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <1236006812.5330.632.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 3aba8d1..a2ee682 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -328,6 +328,8 @@
 	irqreturn_t ret, retval = IRQ_NONE;
 	unsigned int status = 0;
 
+	WARN_ONCE(!in_irq(), "BUG: IRQ handler called from non-hardirq context!");
+
 	if (!(action->flags & IRQF_DISABLED))
 		local_irq_enable_in_hardirq();