On Fri, Jun 26, 2020 at 2:52 PM Kees Cook [off-list ref] wrote:

On Fri, Jun 26, 2020 at 02:09:05PM -0700, Brendan Higgins wrote:

quoted

This patchset adds a centralized executor to dispatch tests rather than
relying on late_initcall to schedule each test suite separately along
with a couple of new features that depend on it.

Sorry it took so long to reply. I got sucked into some other stuff again.

So, the new section looks fine to me (modulo the INIT_DATA change). The
plumbing to start the tests, though, I think is redundant. Why not just
add a sysctl that starts all known tests?

We already have that; however, we use debugfs to start the tests -
same difference. I just find it convenient to not have to build and
then maintain a userland for each architecture. It's also really nice
that KUnit "just works out of the box" - you don't have to download
anything other than the kernel source, and you don't need to do any
steps outside of just run "kuit.py run". That seems like a big
advantage to me.

That way you don't need the plumbing into init/main.c, and you can have
a mode where builtin tests can be started on a fully booted system too.

i.e. boot with "sysctl.kernel.kunit=start" or when fully booted with
"echo start > /proc/sys/kernel/kunit"

And instead of the kunit-specific halt/reboot stuff, how about moving
/proc/sysrq-trigger into /proc/sys instead? Then you (or anything) could
do:

sysctl.kernel.kunit=start sysctl.kernel.sysrq-trigger=b

I think it might be harder to make a case for the reboot stuff without
the stuff I am working on outside of this patchset. I think I will
probably drop that patch from this patchset and reintroduce it later.