free_irq(): fix DEBUG_SHIRQ handling

If we're going to run the handler from free_irq() then we must do it with
local irq's disabled.  Otherwise lockdep complains that the handler is taking
irq-safe spinlocks in a non-irq-safe fashion.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kernel/irq/manage.c

@@ -462,7 +462,9 @@ void free_irq(unsigned int irq, void *dev_id)
 		 * We do this after actually deregistering it, to make sure that
 		 * a 'real' IRQ doesn't run in parallel with our fake
 		 */
+		local_irq_save(flags);
 		handler(irq, dev_id);
+		local_irq_restore(flags);
 	}
 #endif
 }