On Mon, Aug 03, 2020 at 05:37:32PM +0200, Andrey Konovalov wrote:

On Sun, Aug 2, 2020 at 12:25 AM kernel test robot [off-list ref] wrote:

quoted

tree:   https://github.com/hnaz/linux-mm master
head:   2932a9e66c580f3c8d95ec27716d437198fb4c94
commit: 7c0265f304de3c3acd02d0015b56a076357bcce3 [168/421] kasan, arm64: don't instrument functions that enable kasan
config: x86_64-randconfig-r036-20200802 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-14) 9.3.0
reproduce (this is a W=1 build):
        git checkout 7c0265f304de3c3acd02d0015b56a076357bcce3
        # save the attached .config to linux build tree
        make W=1 ARCH=x86_64

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>

All errors (new ones prefixed by >>):

   ld: init/main.o: in function `start_kernel':

quoted

quoted

init/main.c:1012: undefined reference to `efi_enter_virtual_mode'

Hm, I can reproduce the issue, but I don't understand why it happens.

+EFI and KASAN people, maybe someone has an idea.

This is the guilty patch:

https://github.com/hnaz/linux-mm/commit/7c0265f304de3c3acd02d0015b56a076357bcce3

The issue is only with efi_enter_virtual_mode() AFAIU, not with any of
the other functions.

Thanks!

After adding __no_sanitize_address, gcc doesn't inline efi_enabled() on
a KASAN build, even when CONFIG_EFI is disabled, and the function is
just
	return false;
and so it isn't optimizing out the call to efi_enter_virtual_mode().

Making efi_enabled() __always_inline fixes this, but not sure if that is
the correct fix?