[Crash-utility] "cannot access vmalloc'd module memory" when loading kdump'ed vmcore in crash

[Dave Anderson]

----- "Kevin Worth" <kevin.worth at hp.com> wrote:

> Thanks, Dave. Is it valid to just do "make modules" since it appears
> we're just adding a module or does the modification to
> arch/i386/mm/init.c necessitate a rebuilt kernel?

You might be able to *build* crash.o with "make modules", but if
you try to install it, it's going to fail due because it won't
be able to resolve the "page_is_ram" reference.

There may be some other way to export a symbol from
the base kernel without rebuilding the kernel.  I have
seen some 3rd-party modules (i.e., non-Red Hat) that
load a "rogue" module that tinkers with its own internal
exported symbol list after it is installed by overwriting
its own exported symbols with the symbol name and address
of un-exported base kernel symbols.  Then, after the rogue module  
gets installed (and overwrites its own list of exported symbols),
a second "real" module gets installed -- and the real module
uses the illegally-exported (?) kernel symbols from the first
rogue module.  Seems like a violation of the GPL, but anyway,
I don't have any examples of how they do it. 

Dave