RE: [PATCH 1/2 v2] kdump: add the vmcoreinfo documentation

From: Kazuhito Hagio
Date: Wed Dec 05 2018 - 15:31:46 EST


> >> Generating VMCOREINFO is easy in the first kernel, for example:
> >> # makedumpfile -g VMCOREINFO -x vmlinux
> >
> > I get:
> >
> > $ makedumpfile -g VMCOREINFO -x vmlinux
> > The kernel version is not supported.
> > The makedumpfile operation may be incomplete.
> >
> > The vmcoreinfo is saved to VMCOREINFO.
> >
> > makedumpfile Completed.
> >
> > But the text file looks ok AFAICT. Please add that command to the
> > documentation file.
> >

Please note that this VMCOREINFO is generated from the information in
the vmlinux only, not from the running kernel and /proc/kcore. So if
we add a command to dump it from running kernel, it's not suitable.

(This switch is intended to make a data that is used instead of vmlinux
when vmcore didn't have VMCOREINFO and makedumpfile is in a situation
that we don't have vmlinux. Please see the explanation of the -i and
-g options in makefumpfile(8).)

makedumpfile doesn't have any switch which dumps VMCOREINFO from kcore
for now. (I'm thinking to have makedumpfile dump it as debug message,
though.)

Thanks,
Kazu