Hi Kamal, Sasha,

On Mon, Dec 7, 2020 at 11:42 PM Kamal Mostafa kamal@canonical.com wrote:

On Fri, Dec 04, 2020 at 10:28:46AM -0800, Kamal Mostafa wrote:

...

Hi Sasha-

This v5.4.78 commit breaks the tools/testing/selftests/bpf build:

[linux-5.4.y] c602ad2b52dc bpf: Zero-fill re-used per-cpu map element

Like this:

  prog_tests/map_init.c:5:10: fatal error: test_map_init.skel.h: No such file or directory
      5 | #include "test_map_init.skel.h"

Because tools/testing/selftests/bpf/Makefile in v5.4 does not have the "skeleton header generation" stuff (circa v5.6).

Reverting c602ad2b52dc from linux-5.4.y fixes it.

Another option would be to just drop the selftest from linux-5.4.y, but keep the beneficial change to kernel/bpf/hashtab.c.

(We're leaning towards that approach for Ubuntu).

-Kamal

An alternative could be to use the initial version of the selftest I had proposed before learning about the skeleton approach.

You can find it here: https://lore.kernel.org/bpf/20201029111730.6881-1-david.verbeiren@tessares.n...

I also think it would be good to keep the fix of course.

-David