Compiling makedumpfile from source

manty kuma mantykuma at
Thu Jul 8 18:45:57 PDT 2021

Hi Kazuhito san,

I am looking to better understand the sections being filtering out
with each of the following options.

Zero page:
Pages that are empty. Ignoring these pages won't have any impact on analysis.

non-private cache and private cache:
What exactly are these sections of memory? Just a one-line overview
about them is sufficient.
(My understanding was that cache is not part of RAM. Is this cache
something else? Like some bookkeeping data maintained by the kernel?)

user data:
Are these sections of the memory for the user space processes/memory
sections allocated using malloc?
My understanding is that If I exclude this section, gcore would not
work. Is my understanding correct?
I expected this section to be big. But in fact excluding this did not
have much impact on the dump size.

free page:
unallocated pages. Since they are not allocated. filtering them out
won't have any impact on dump analysis.
Please correct me if I am wrong.

If there is already some place that explains what these sections
filter out, please just drop the reference to them and i will look
into it.
Thank you very much in advance!


On Thu, Jul 8, 2021 at 8:17 PM manty kuma <mantykuma at> wrote:
> Sorry. I am not sure how but I completely missed this email.
> Yes, /tmp was not available in my env. I just did mkdir before
> executing `makedumpfile` and it is now working well.
> Thank you very much.
> On Mon, Jun 28, 2021 at 4:07 PM HAGIO KAZUHITO(萩尾 一仁)
> <k-hagio-ab at> wrote:
> >
> > -----Original Message-----
> > > Hi Kazuhito san,
> > >
> > > I am getting the following error when trying to use makedumpfile utility.
> > >
> > > > copy_vmcoreinfo: Can't open the vmcoreinfo file(/tmp/vmcoreinfoLUQc25). No such file or directory.
> > > > makedumpfile Failed
> > >
> > > In your setup how are you providing the vmcoreinfo file? In my case it
> > > is checking /tmp/vmcoreinfoLUQc25
> > > Who generates this file?
> >
> > Generally, vmcoreinfo is copied from vmcore's ELF note to /tmp/vmcoreinfoXXXXXX
> > by makedumpfile, please see copy_vmcoreinfo().  So no need to provide explicitly.
> >
> > Is there the /tmp directory on your environment?
> >
> > Kazu
> >
> >

More information about the kexec mailing list