Missing panic logs in /var/log/kern.log

[Greg KH]

On Tue, Jun 01, 2021 at 02:33:50PM +0900, manty kuma wrote:
> I just triggered a panic, expecting that the logs will be visible in
> `/var/log/kern.log` after reboot, but there are no logs present there.

I have never heard of kernel logs being written to that location, what
tool do you have that does that and where is that documented?

> Considering I have no access to the serial port, how do I know what went
> wrong?

When the kernel panics, it usually can not write to the disk, so it's a
bit hard to save anything :)

That being said, there are ways the kernel can save the crash
information, look into the "pstore" interface and see if that will work
for your hardware platform (it requires hardware to store the
information across boots.)

good luck!

greg k-h