Re: [PATCH] xarray: port tests to kunit

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Liam,

On Thu, 30 Jan 2025 at 13:52, Liam R. Howlett <Liam.Howlett@oracle.com> wrote:
> * Geert Uytterhoeven <geert@linux-m68k.org> [250130 03:21]:
> > On Wed, 29 Jan 2025 at 23:26, Liam R. Howlett <Liam.Howlett@oracle.com> wrote:
> > > I've never used the kunit testing of xarray and have used the userspace
> > > testing instead, so I can't speak to the obscure invocation as both
> > > commands seem insanely long and obscure to me.
> >
> > The long and obscure command line is a red herring: a simple
> > "modprobe test_xarray" is all it takes...
>
> That command worked before too...

Exactly, great!

> > > You should look at the userspace testing (that this broke) as it has
> > > been really useful in certain scenarios.
> >
> > BTW, how do I even build tools/testing/radix-tree?
> > "make tools/help" doesn't show the radix-tree test.
> > "make tools/all" doesn't seem to try to build it.
> > Same for "make kselftest-all".
>
> make

Where?

> Or look at the make file and stop guessing.  Considering how difficult

There is no Makefile referencing tools/testing/radix-tree or the
radix-tree subdir. That's why I asked...

Oh, I am supposed to run make in tools/testing/radix-tree/?
What a surprise!

Which is a pain when building in a separate output directory, as you
cannot just do "make -C tools/testing/radix-tree" there, but have to
type the full "make -C tools/testing/radix-tree O=..." (and optionally
ARCH=... and CROSS_COMPILE=...; oh wait, these are ignored :-( in the
source directory instead...

If these tests are not integrated into the normal build system (see
also [1]), I am not so surprised the auto-builders don't build them,
and breakages are introduced...

> it is to get m68k to build, you should probably know how to read a
> makefile.

Like all other kernel cross-compilation? Usually you don't even have
to know where your cross-compiler is living:

    make ARCH=m68k

> > When trying the above, and ignoring failures due to missing packages
> > on my host:
> >   - there are several weird build errors,
> >   - this doesn't play well with O=,
> >   - lots of scary warnings when building for 32-bit,
> >   - ...
> >
> > At least the kunit tests build (and run[1] ;-) most of the time...
>
> Do they?  How about you break something in xarray and then try to boot
> the kunit, or try to boot to load that module.

If you break the kernel beyond the point of booting, you can indeed
not run any test modules...

Which does _not_ mean the userspace tests are not useful, and that I
approve breaking the userspace tests...

[1] https://lore.kernel.org/all/CAK7LNASdA+5_pdTjr1dY-cKGSDq804Huc_CX_8-Gg+ypFCmajQ@mail.gmail.com/

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds