Re: [gentoo-user] Re: my 5.15.93 kernel keeps rebooting

[John Covici <covici@ccs.covici.com>]

On Thu, 16 Feb 2023 12:37:51 -0500,
Laurence Perkins wrote:
> 
> 
> 
> >-----Original Message-----
> >From: John Covici <covici@ccs.covici.com> 
> >Sent: Wednesday, February 15, 2023 7:20 AM
> >To: gentoo-user@lists.gentoo.org
> >Subject: Re: [gentoo-user] Re: my 5.15.93 kernel keeps rebooting
> >
> >On Wed, 15 Feb 2023 09:50:27 -0500,
> >Grant Edwards wrote:
> >> 
> >> On 2023-02-14, Rich Freeman <rich0@gentoo.org> wrote:
> >> 
> >> > Where are you getting this from, the system log/journal?  This 
> >> > doesn't seem like a clean shutdown, so if it is a kernel PANIC I 
> >> > wouldn't expect the most critical info to be in the log (since it 
> >> > will stop syncing to protect the filesystem).  The details you need 
> >> > probably will be displayed on the console briefly.  You can also 
> >> > enable a network console, which will send the dmesg output 
> >> > continuously over UDP to another device.  This won't be interrupted 
> >> > by a PANIC unless there is some issue with the hardware or networking stack.
> >> 
> >> If you've got a serial port[1], you could also set up serial logging. 
> >> Though using serial ports have become a bit of a lost art, the serial 
> >> console code in the kernel is pretty carefully designed to be the last 
> >> man standing when things start to die. It's possible (though I 
> >> wouldn't say probable) that a serial console will be able to show you 
> >> stuff closer to the event horizon than a network console can.
> >> 
> >> Anyway, since still I'm in the serial port business (yes, there are 
> >> still plenty of people using serial ports in industrial settings) I 
> >> had to mention it...
> >> 
> >> [1] For this purpose you want a plain old UART on the motherboard type
> >>     seial port. You'd be surprised how many motherboards still have
> >>     them. Even though they're never brought out to a DB9 connector on
> >>     the back panel, there's often an 8-pin header on the edge of the
> >>     board somewhere, so you'd need one of these:
> >> 
> >>     
> >> https://www.amazon.com/C2G-27550-Adapter-Bracket-Motherboards/dp/B0002
> >> J27R8/
> >
> >I do have one which I use for my speech synthesizer.  I also have one on my other box which I could hook up -- if I can find my null modem cable.  I think I will try the netconsole first and the serial console if that does not work.
> >
> >Thanks for the hint.
> >
> >
> https://wiki.gentoo.org/wiki/Kernel_Crash_Dumps  is another option if you're somehow not getting enough information out of the console.  More complex to set up, but you can take an actual debugger to the result and hopefully find out exactly what's going on.

Second try, don't know what happened.

So, after not getting any results from net console and somehow my null
modem cable only seemed to work from another computer  to the one with
the problem kernel, I am trying to figure out how to set up for
getting a crash dump.

When looking at the article, it seems to want a root partition -- I
use zfs, which automatically detects the root partition, so can I just
forget about that one?

Also I am using systemd, so there is no /etc/local.d, but I do have
another location where I put commands  to run after everything else
has run -- do I put the start up script there?

Also, there is a file /etc/conf.d/kexec.conf and I got a notice to
move it to /etc/kexec.conf, what do I put there?


-- 
Your life is like a penny.  You're going to lose it.  The question is:
How do
you spend it?

         John Covici wb2una
         covici@ccs.covici.com