Hi Siwei. I have some problem with my sel4 project, as you know, I'm work on my master project and develop a project on sel4 (camkes) which provide filesystem interfaces, and use ethernet and lwip network stack. This section is ok but sometimes my project crashed and my threads failed. In another words, I wrote my components and its work correctly but some times (rarely) my threads crashes and I couldn't find problem. So i decide to use a service like watch dog timer for garanty all of threads work and when one of therm failed or crashed, this mechanism detect it and start another thread or reset the system. A simple solution can implement is use some thread controlling (implement WDT in user mode). But I want to know is there in camkes or sel4 any mechanism for this need? a mechanism for garanti stability and system availability? can any body help me? Is there anybody which confront with this need?