exclude UNDEF global syms from lookup_global_symbol

Don't return a result for an UNDEF symbol

Signed-off-by: Seth Jennings <sjenning@redhat.com>
add module patching support to create-diff-object

This commit adds module patching support to create-diff-object by:

1) generalizing the vmlinux CLI parameter
2) adding the kernel object name to each patch and dynrela
3) adding slightly different logic for vmlinux/module in the dynrela
creation

Signed-off-by: Seth Jennings <sjenning@redhat.com>
add module patching support to core module

This commit adds support for patching modules.  If a patch or dynrela is
determined to be for a kernel module, the old_offset/src is not used and
the symbol location is looked up using kallsyms.  The module being
patched is also references to keep if from disappearing from underneath
us.

This commit introduces early and limited support.  The kernel module to
be patched must already be loaded or the patch module will not apply.

Signed-off-by: Seth Jennings <sjenning@redhat.com>
add module for testing module patching

A simple kernel module for testing basic kernel module patching.

Just run doit.sh from test/testmod.

Signed-off-by: Seth Jennings <sjenning@redhat.com>