Re: [PATCH v4 1/2] selftests: run tests on nommu architecture

["Lorenzo Stoakes (ARM)" <ljs@kernel.org>]

On Wed, Sep 30, 2026 at 08:57:10AM +0900, Hajime Tazaki wrote:
> Architectures lacking MMU don't support fork(2) syscall and only
> vfork(2) is available with limitations.  Thus, we cannot run kselftest
> on nommu architecture as is.
>
> This commit addresses this issue with the following changes:
>
> - on test run stage, avoid calling timeout command when NOMMU=1 variable
>   added to environmental variable, since timeout command uses fork
>   syscall which nommu platform doesn't support.
> - describe the difference of nommu tests in the document.
>
> So command line to build/execute tests for nommu should be like below:
>
>  $ make ARCH=um NOMMU=1 O=build kselftest-all TARGETS=nommu
>  $ make ARCH=um NOMMU=1 O=build kselftest-install TARGETS=nommu
>  $ NOMMU=1 ./build/kselftest/kselftest_install/run_kselftest.sh -p \
>    -c nommu
>
> Cc: Shuah Khan <shuah@kernel.org>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: Kees Cook <kees@kernel.org>
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Will Drewry <wad@chromium.org>
> Cc: Mark Brown <broonie@kernel.org>
> Cc: Brendan Jackman <brendan.jackman@linux.dev>
> Cc: Hangbin Liu <liuhangbin@gmail.com>
> Cc: "Ricardo B. Marliere" <rbm@suse.com>
> Cc: linux-kselftest@vger.kernel.org
> Cc: linux-um@lists.infradead.org
> Cc: linux-mm@kvack.org
> Cc: linux-doc@vger.kernel.org

Not sure we need all the Cc's explicitly :) Andrew adds them in (I'm actually
not sure in general if they're really all that useful, some of my series sent to
hoards of people due to touching multiple bits scroll off the screen :P)

> Closes: https://sashiko.dev/#/patchset/20260813063401.1786548-1-thehajime%40gmail.com
> Signed-off-by: Hajime Tazaki <thehajime@gmail.com>

LGTM so:

Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>

--
Cheers, Lorenzo