spin_lock_irq(&undef_lock); 
unsigned long flags;  spin_lock_irqsave(&undef_lock, flags); 
void register_undef_hook(struct undef_hook *hook){	spin_lock_irq(&undef_lock);	list_add(&hook->node, &undef_hook);	spin_unlock_irq(&undef_lock);}
4520	/local/tlutelli/issta_data/temp/c/2005_temp/2005/4520/109d89ca0ee76138e04b41726b7f719c7df65e88/traps.c/buggy/arch/arm/kernel/traps.c