Compile external module against linux source and use functionality in linux source

[Arjun Pandey]

Hi Valdis

That makes sense :)
Moving the module to the kernel makes it work.

Thanks
Arjun

On Thu, Sep 25, 2014 at 5:57 PM,  <Valdis.Kletnieks at vt.edu> wrote:
> On Thu, 25 Sep 2014 10:49:33 +0530, Arjun Pandey said:
>
>> Step 1 goes through fine. The module gets compiled fine.
>> However now when i try to compile the kernel i get linker error of
>> undefined reference to the function exported from the kernel module.
>>
>> I can't find any documentation on this usecase.
>
> In general, things that are built-into the kernel with CONFIG_FOO=y
> are *not* allowed or able to reference symbols that are in a module.
>
> This is because a module can potentially not be loaded (consider system
> boot before you're up far enough to do a modprobe, as an important
> special case), at which point trying to call the non-existent module
> gets you an oops or panic.
>
> So you can't find any doc on it because it's not supported.