Kernel Panic Logs

Hi everybody,

I am trying to port a driver to work on the AGX Xavier. So far it has yet to work properly, and I have been using the resulting kernel logs to see what is going wrong and make changes accordingly. On the most recent change, the program crashes the Jetson completely, and saves nothing in terms of kernel logs. I would assume this is due to a kernel panic, where the system won’t access memory to write the logs.

My question is how can I access the logs so that I can see what exactly is happening in the kernel. I have tried running the program over SSH (no error output) and using kdump (won’t work on L4T). The only thing I have had any luck with is disabling the GUI and running everything through the CLI, which displayed the kernel error logs to the screen before crashing. Unfortunately the printing is so quick that I only have a chance to see the bottom page of logs before the system reboots. However, if this output can be saved before crashing somehow, it could be a way to get the logs.

Any advice on how to save or at least see the kernel logs would be appreciated.

Thanks,
John

Use serial console. Serial console programs can log a session. Serial consoles also have very few requirements, and can survive even when most of the system is dead. The official docs mention how to do this with the micro-B USB port.

Once logged in through the serial console you could for example run “dmesg --follow”, and this will show log lines as they occur. Or “sudo tail -f /var/log/kern.log”. You will get logs further into the failure, and everything will be nicely packaged as a log file.

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