Testing the whole series, I found that some Landlock tests are flaky
starting with this patch. I tried to not use the longjmp in the
grandchild but it didn't change. I suspect missing volatiles but I
didn't find the faulty one(s) yet. :/
I'll continue investigating tomorrow but help would be much appreciated!
On Wed, Feb 28, 2024 at 04:59:09PM -0800, Jakub Kicinski wrote:
> From: Mickaël Salaün <mic@xxxxxxxxxxx>
>
> Replace Landlock-specific TEST_F_FORK() with an improved TEST_F() which
> brings four related changes:
>
> Run TEST_F()'s tests in a grandchild process to make it possible to
> drop privileges and delegate teardown to the parent.
>
> Compared to TEST_F_FORK(), simplify handling of the test grandchild
> process thanks to vfork(2), and makes it generic (e.g. no explicit
> conversion between exit code and _metadata).
>
> Compared to TEST_F_FORK(), run teardown even when tests failed with an
> assert thanks to commit 63e6b2a42342 ("selftests/harness: Run TEARDOWN
> for ASSERT failures").
>
> Simplify the test harness code by removing the no_print and step fields
> which are not used. I added this feature just after I made
> kselftest_harness.h more broadly available but this step counter
> remained even though it wasn't needed after all. See commit 369130b63178
> ("selftests: Enhance kselftest_harness.h to print which assert failed").
>
> Replace spaces with tabs in one line of __TEST_F_IMPL().
>
> Cc: Günther Noack <gnoack@xxxxxxxxxx>
> Cc: Shuah Khan <shuah@xxxxxxxxxx>
> Cc: Will Drewry <wad@xxxxxxxxxxxx>
> Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxx>
> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
> --
> v4:
> - GAND -> GRAND
> - init child to 1, otherwise assert in setup triggers a longjmp
> which in turn reads child without it ever getting initialized
> (or being 0, i.e. we mistakenly assume we're in the grandchild)
Good catch!
