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xSemaphoreGive in critial section

Posted by paha11 on December 22, 2014


I wonder if it's possible to call xSemaphoreGive withing critical section. Something like

taskENTERCRITICAL(); .... xSemaphoreGive(AppTasks[curr->taskId].loopSem); .... taskEXIT_CRITICAL();

I used it in situation where needed to do some linked list operation.

From the source code of FreeRTOS 7.0.0 of function xQueueGenericSend(..) in queue.c I saw that immediate task swith can be made so the above code shall be NO NO? Thank you for any comment Regards

xSemaphoreGive in critial section

Posted by davedoors on December 22, 2014

The rule is dont do it, but you might get away with it on a give depending on task priorities. At best the wrong task might be scheduled because a context switch away cant happen, at worst you will get a horrible logic error and crash for the same reason. Definitely dont do it on a take!

xSemaphoreGive in critial section

Posted by paha11 on December 23, 2014


thanks for the link. That's what I was looking for. Regards Pavel

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