On Tue, Feb 13, 2018 at 2:32 AM, Michal Hocko [off-list ref] wrote:

On Tue 13-02-18 21:16:55, Michael Ellerman wrote:

quoted

Kees Cook [off-list ref] writes:

quoted

On Mon, Feb 12, 2018 at 7:25 PM, Michael Ellerman [off-list ref] wrote:

quoted

Michal Hocko [off-list ref] writes:

quoted

Hi,
my build test machinery chokes on samples/seccomp when cross compiling
s390 and ppc64 allyesconfig. This has been the case for quite some
time already but I never found time to look at the problem and report
it. It seems this is not new issue and similar thing happend for
MIPS e9107f88c985 ("samples/seccomp/Makefile: do not build tests if
cross-compiling for MIPS").

The build logs are attached.

What is the best way around this? Should we simply skip compilation on
cross compile or is actually anybody relying on that? Or should I simply
disable it for s390 and ppc?

The whole thing seems very confused. It's not building for the target,
it's building for the host, ie. the Makefile sets hostprogs-m and
HOSTCFLAGS etc.

So it can't possibly work with cross compiling as it's currently
written.

Either the Makefile needs some serious work to properly support cross
compiling or it should just be disabled when cross compiling.

Hrm, yeah, the goal was to entirely disable cross compiling, but I
guess we didn't hit it with a hard enough hammer. :)

Do you know why it is written that way? Why doesn't it just try to cross
compile like normal code?

No idea, sorry. All I know about this code is that it breaks my build
testing.

IIRC, one of the problems is with build ordering problems: the kernel
headers used by the samples aren't available when cross compiling.

I'm happy to kill it entirely with Michal's patch, though. Feel free
to carry in your tree!

Acked-by: Kees Cook <redacted>

-Kees

-- 
Kees Cook
Pixel Security