Priority Inversion

The most common RTOS priority mistake is assigning priorities by business importance.

For example:

control task is most important -> highest priority
communication is also important -> next priority
logging is not important -> lowest priority

This is intuitive, but not enough. RTOS priority decides which ready task runs first. It is not the same as business value, and it does not guarantee that a high-priority task finishes first.

The first model is:

Many concurrency bugs trigger the same first reaction: add a lock. That is only half right.

A lock can protect shared state, but it does not make concurrency problems disappear. It turns “multiple execution flows modify data at the same time” into rules about who enters first, who waits, and who releases. If those rules are poorly designed, the system may stop corrupting data and instead start hanging, stalling, timing out, or delaying high-priority work.