makedumpfile-1.4.4: Support for LZO compression.

[Atsushi Kumagai]

Hello Louis,

On Thu, 31 May 2012 13:43:29 +0200
Bouchard Louis <louis.bouchard at canonical.com> wrote:

> Hello Kumagai-san,
> 
> Le 31/05/2012 12:48, Bouchard Louis a écrit :
> > 
> > There seems to be some issue in get_mem_type() that I will try to debug
> > further. Please let me know if you have something specific that you want
> > me to test and/or try as I have everything needed.
> > 
> > Kind regards,
> > 
> > ...Louis
> > 
> > 
> 
> Here is some more details about the issue. I have recompiled
> makedumpfile with symbols in order to debug the issue. The following
> code seems to be interesting :
> 
> get_mem_type(void)
> {
> 	int ret;
> 
> 	if ((SIZE(page) == NOT_FOUND_STRUCTURE)
> 	    || (OFFSET(page.flags) == NOT_FOUND_STRUCTURE)
> 	    || (OFFSET(page._count) == NOT_FOUND_STRUCTURE)
> 	    || (OFFSET(page.mapping) == NOT_FOUND_STRUCTURE)) {
> 		ret = NOT_FOUND_MEMTYPE;
> 
> (gdb) p size_table.page
> $1 = 64
> (gdb) p offset_table.page
> $2 = {flags = 0, _count = -1, mapping = 8, lru = -1}
> 
> So offset_table.page._count = -1, which triggers the NOT_FOUND_MEMTYPE.
> 
> I am not familiar enough with this to conclude, but you might have an
> idea. I can have the vmlinux file made available to you if you want.
> 
> For information, I am also working with John Wright who is the debian
> package maintainer to assist him in packaging makedumpfile for Debian
> and Ubuntu.

I'm sorry, it seems a bug related to kernel 3.1 or later.
Even current makedumpfile can't get the offset of page._count and page.lru 
from vmlinux.

Thank you for your report. I will fix this bug.

BTW, do you need vmcoreinfo file ? If your purpose is only to generate dumpfile,
you can execute makedumpfile without -g option.
Because the vmcore generated by kernel 2.6.24 or later include the debug
information which makedumpfile need.

Example:

 $ makedumpfile vmcore dumpfile


Thanks
Atsushi Kumagai