[PATCH] warn if free_irq() is called from IRQ context

Warn if free_irq() is called in IRQ context - free_irq() can execute /proc
VFS work, which must not be done in IRQ context.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

kernel/irq/manage.c

@@ -271,6 +271,7 @@ void free_irq(unsigned int irq, void *dev_id)
 	struct irqaction **p;
 	unsigned long flags;
 
+	WARN_ON(in_interrupt());
 	if (irq >= NR_IRQS)
 		return;