On Tue, Nov 30, 2021 at 5:55 PM Fotis Panagiotopoulos <f.j.pa...@gmail.com> wrote:
> Hello everyone, > > I have some issues with the watchdogs and possibly the scheduling of the > kernel. > > I am not sure if this is a bug, or if I am miss-using something... > > I am working on an STM32F427, and I am using the independent watchdog > timer. > I have enabled the watchdog automonitor using a timer > (WATCHDOG_AUTOMONITOR_BY_TIMER). > Generally it works correctly. > > At one point in my application, there are some writes to the MCU Flash > memory. > There are multiple calls (5-6) to the write functions, so writing all these > data takes quite some time. > > During these writes, the hardware watchdog (IWDG) expires, and restarts the > system. > As far as I can tell the kernel watchdog (timer) never fires. > So, the auto-monitor stops working. > > This seems a bit odd to me, for two reasons: > > 1. I couldn't find anywhere in the progmem driver anything that disables > interrupts. > I think that the kernel should tick properly during the Flash writes. > > Even though nobody disables interrupts, the OS may be stuck sometimes(~10ms) because flash can't write and read at the same time. > 2. Even if for some reason the kernel is locked during the write, I would > expect a reschedule when the write finishes. > As said, there are 5-6 calls, so between these calls shouldn't the kernel > check for other tasks ready to run? > Yes, the schedule should happen between each call. > And of course check for any watchdogs ready to run and thus also run the > auto-monitor? > > Do I understand anything wrong? > > In any case, what is the proper way to overcome this issue? > > You can enable SCHED_CRITMONITOR related config to find why the kernel stops the scheduling: incubator-nuttx/Kconfig at master ยท apache/incubator-nuttx (github.com) <https://github.com/apache/incubator-nuttx/blob/master/sched/Kconfig#L707-L793> > Thank you! >
