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 <[e-mail]>
Cc: David Woodhouse <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

kernel/irq/manage.c

···
 		 * 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
 }