FreeRTOS does not execute first task after 'svc 0' call

[hs2 (Hartmut Schaefer)]

I’m not familiar with libopencm3 but maybe there is an issue with the FreeRTOS awareness means the 3 exception handlers mandatory for FreeRTOS.
Have a look here if it brings you a step further:

FreeRTOS newbie - STM32F103 + libopenCM3 + build errors

Thanks for reporting back. In your case, the definition of configSYSTICK_CLOCK_HZ is optional, so I can’t understand how defining it fixed the issues you were having. When you define that symbol, FreeRTOS configures the SysTick a little differently, but that shouldn’t have impacted anything of any consequence in your case. Also it’s best to avoid that file you mentioned, opencm3.c. The PendSV handler is intended to be the ISR, not to be called from the ISR. If the PendSV handler is called f…