[SOLVED] API OS_InInterrupt() doesn't work if called inside function called by OS SW timer

We are using OS version: V5.18.0.3

We have a function that uses mutex, and it is used inside tasks and in ISR function.
In order to avoid OS error, mutex usage is under condition, checking if caller is in task execution or in ISR exection, using API OS_InInterrupt()
See example code below

void doSomething(void)
{
   bool isISR = FALSE;
   // check if it is called inside ISR
   isISR = (OS_InInterrupt()) ? TRUE : FALSE;
   // thread safe access if caller is NOT an ISR
   if ( isISR == FALSE )
   {
      OS_Use(&some_mutex);
   }
   // do something code
   // thread safe access if caller is NOT an ISR
   if ( isISR == FALSE )
   {
      OS_Unuse(&some_mutex);
   }
}

This solution works fine and as expected from embos documentation for API OS_InInterrupt() in both scenarios

BUT, instead, if the same function is used as callback for a timer SW (where caller is OS code that is called in OS sysTick ISR), API OS_InInterrupt() return WRONG value (it returns "NO isr"),
so our code goes in OS_error function for invalid usage of OS API inside an ISR

I didn't see any other way for our code to understand if caller is task code or SW timer, so i think this is an API bug

Attached screenshot from debugging:
(1) timer with callback and mutex create
(2) debug inside function called by SW timer, where isISRtest from OS_InInterrupt() is showed with wrong value
(3) after this, mutex function is called and code goes in OS_error

Hi, thanks for quick reply

Your explanation is very clear, and also help us in undertstanding better where OS timer SW are called ("Cortex-M embOS software timers are executed within the PendSV()")

Your workaround seems works fine in my tests.

I defined a macro like this:
// check OS SW timer context
#define OS_IS_SW_TIMER_CONTEXT() ((NULL != OS_TIMER_GetCurrent()) ? 1:0)

and now our code tests both conditions using (OS_InInterrupt() || OS_IS_SW_TIMER_CONTEXT() )

Let me suggest to add this macro or something similar also in EMBOS macros.