I used rt_mutex_lock to protect one critical section in softirq-rx code . There is some kernel crash happens in the critical section . In my OOPs analysis i found that .. PC- > my function code in critical section LR -> rt_mutex_unlock . Why LR is rt_mutex unlock ? Before unlocking , preemption can happen ? Thanks, Ratheesh -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html