[RTOS Support] vTaskSwitchContext() usage of listGET

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vTaskSwitchContext() usage of listGET_...

Posted by Robert Warner on October 22, 2008

vPreemptiveTick() calls vTaskSwitchContext() usage of listGET_OWNER_OF_NEXT_ENTRY() causes __dabt(). Unfortunately there is no task at this point to execute.

This appears to be a race condition of letting the tick counter generate ticks while tasks are just getting initialized. I assume the tick generation should not occur until after the tasks have been initialized and prior to vTaskStartScheduler(). Now locating where the tick generation has been initiated.

RE: vTaskSwitchContext() usage of listGET_...

Posted by Dave on October 22, 2008

You have not mentioned which port you are using. If using Cortex M3 then this can happen if you attempt to block from within a critical section. It can also happen on any port if you have your interrupt priorities wrong, that is you are using API calls from an interrupt priority about the maximum allowable system call interrupt priority.