What i learned that - softirq cannot be put into sleep mode .( Am i right ) ? I am facing a problem in my RT linux . I used rt_mutex_lock to protect one critical section in softirq-rx code . There is some kernel crash happens in the critical section . PC- > my function in critical section LR -> rt_mutex_unlock . Why LR is rt_mutex unlock ? If rt_mutex_lock can sleep , softirq-rx may sleep ? Thanks, Ratheesh -- To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html