reset crashed linux side from sketch

Sometimes my linux side seems to crash (white LED goes out and I can not connect anymore).

I have 2 questions: - can I reset the Yun (linux side, or linux + sketch) from the sketch side? I can easily detect from the MCU that the linux side is dead. But is there a way that I can reset the linux side without having to rely on Bridge, etc... is there an existing connection from the MCU to CPU that allows this? - if my linux side crashes, is there somewhere a log that I can consult to see what has gone wrong?

NewLine: - can I reset the Yun (linux side, or linux + sketch) from the sketch side? I can easily detect from the MCU that the linux side is dead. But is there a way that I can reset the linux side without having to rely on Bridge, etc... is there an existing connection from the MCU to CPU that allows this?

You can use Process and execute a "reboot", that will reset linux. Or you may autoreset the sketch, again using Process with "reset-mcu" Unfortunately there is no way to detect that the linux side has booted (ATM). We judged hardware suggestions such as https://gist.github.com/wayoda/db3c023417757f726088 impractical because of the cost.

NewLine: - if my linux side crashes, is there somewhere a log that I can consult to see what has gone wrong?

You should understand what is making it crashing and add some log file to it. Most likely, the yun ran out of memory and rebooted. Try to spot the memory hog

I can not use Process to reset the linux side as this uses the Bridge, and this is no longer functional (you should assume the linux side is not operational, but also does not auto-reboot. I was asking for something that does not use the Bridge (or any other thing that relies on an operational linux side). So I am more looking for something "hardware like". Is there no MCU output pin that is in some way connected to the CPU reset?

I dont need to know when the linux side has booted, but that doesnt seem so difficult, is it? Just have a simple process that will do a simple handshaking over the bridge (initiated by the sketch). If the sketch gets an answer, the Linux side has booted. I am doing just that, but the other way around.

Ah sorry I missed that. Then no, sorry again, I don't know how to do it.

No problem.

In theory if I could pull the RST pin of the CPU low by one of the MCU outputs, that would cause the CPU to reset? (would just look as if I pressed the Yun RST button) It should not be too difficult to add some circuitry that does this, I guess?

Arnatively, I assume the Atheros has a watchdog? How is this setup in the OpenWrt-Yun? Is it enabled?

[edit]: I just saw that there is indeed a watchdog process kicking it every 5 sec.