Re: [kernel-hardening] Re: [PATCH] lkdtm: Add tests for LIST_POISON and ZERO_SIZE_PTR

[Michael Ellerman]

kbuild test robot <lkp@xxxxxxxxx> writes:
> [auto build test ERROR on char-misc/char-misc-testing]
> [also build test ERROR on v4.9-rc5]
> [cannot apply to next-20161115]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url:    https://github.com/0day-ci/linux/commits/Michael-Ellerman/lkdtm-Add-tests-for-LIST_POISON-and-ZERO_SIZE_PTR/20161115-235441
> config: i386-randconfig-i0-201646 (attached as .config)
> compiler: gcc-4.8 (Debian 4.8.4-1) 4.8.4
> reproduce:
>         # save the attached .config to linux build tree
>         make ARCH=i386 
>
> All errors (new ones prefixed by >>):
>
>>> ERROR: "mmap_min_addr" [drivers/misc/lkdtm.ko] undefined!

I couldn't see what was causing this, but of course it's just that
mmap_min_addr is not exported, and in that config LKDTM is a module.

I always build it in which is why I didn't notice.

I'm not sure we want to EXPORT_SYMBOL mmap_min_addr just for this test
do we? I could change the test to use mmap_min_addr if LKDTM is
built-in, and otherwise just map at zero. Dunno.

cheers