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

[manty kuma]

pstore looks very promising. I tried pstore with backup as efivars and it
works.

Although efivars works, I would like to use the pstore with ramoops and I
am currently having difficulty in choosing the correct ramoops.mem_address.

I enabled the related configs and using command line parameters as shown in
the documentation
https://www.kernel.org/doc/html/v4.14/admin-guide/ramoops.html

Ex usage is: `mem=128M ramoops.mem_address=0x8000000 ramoops.ecc=1`
0x8000000 is the start of the kernel code section according to
`/proc/iomem`. So, I need to find a different location.

In /proc/iomem I can see a few sections of ram marked as "System RAM" and
"Reserved"
I tried to use these addresses but using them causes weird behavior and the
system is freezing while booting up.
*So, how do I select a 128 MB space on my ram and dedicate it for ramoops?*


On Tue, Jun 1, 2021 at 5:40 PM Fox Chen <foxhlchen at gmail.com> wrote:

> On Tue, Jun 1, 2021 at 2:07 PM manty kuma <mantykuma at gmail.com> wrote:
> >
> > I am using debian , the logging system being used is rsyslogd.
> > in /etc/rsyslog.d/default.conf we have rule as follows:
> > ```
> > kern.* /var/log/kern.log
> > ```
> > This rule I believe is the reason why all the kernel logs are being
> redirected to /var/log/kern.log.
> >
> > Also dmesg does not show anything. So, i am pretty sure that all the
> kernel logs are being handled solely by `rsyslogd`
> > And this is just the default debian distribution without any
> customizations.
> >
> > Thank you for the 'pstore' clue. I will explore it further.
> >
> > On Tue, Jun 1, 2021 at 2:42 PM Greg KH <greg at kroah.com> wrote:
> >>
> >> 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.)
>
> Also, check kdump, I think it can help as well.
>
> >> good luck!
> >>
> >> greg k-h
> >
> > _______________________________________________
> > Kernelnewbies mailing list
> > Kernelnewbies at kernelnewbies.org
> > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20210607/188f3dc3/attachment.html>