Security and critical threads

Any thread can make itself critical, and any designer can make any sigevent critical (meaning that it will cause the eventual receiver to run as critical), but this isn't a security issue. That's because a thread marked as critical has no effect on the thread scheduler unless the thread is in a partition that has a critical budget. The thread scheduler has security options that control who may set or change a partition's critical budget.

For the system to be secure against possible critical thread abuse, it's important to: