How to analyse crash dumps?

ArduCopter Copter 4.2
1

Today my 9" quad using PixRacer and Copter 4.2.2 started misbehaving wildly after I played a little with filters. It continued to do nonsense even when I rolled the parameters back to safe values.

Among everything else, it kept telling me that it saved @SYS/crash_dump.bin. I took it out of the quad using mavproxy, but I cannot understand how to analyse it, and how to understand what exactly is broken.

Could you please point me to it? Just in case, the dump itself is attached.
crash_dump.bin (237.1 KB)
mav.parm (20.3 KB)

2

A notch center frequency of 20Hz with a bandwidth of 10Hz? You have applied the filter in the RC control range.

3

That’s the notch that based on the ESC telemetry (INS_HNTCH_MODE=3), so the frequency to bandwidth ratio is what counts anyway.

I mean, it flew nearly perfectly, at least on smaller speeds, with only small jitter visible on an HD camera, that I was fighting with. I added a second harmonic notch (the one based on FFT), it ran out of memory, and this was roughly the moment things started to go wrong even when I turned the second notch back off.

4

There is a YouTube video (pretty sure it’s YouTube at least) where one of the devs walks through analyzing a number of log files.

5

Anyway, it seems like that crash dump has nothing in common with my problems (unless I have the second IMU also dying together with the first one). However, it is still not very clear for me how to understand the reason of the crash from the crash dump.

6

For others looking at how to analyze the crash_dump.bin file, I was also curious and directed to Tools/debug/crash_debugger.py which is documented in the README: https://github.com/ArduPilot/ardupilot/tree/master/Tools/debug#getting-fault-dump-via-flash

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