Re: [PATCH v4 4/4] selftest: Taint kernel when test module loaded

[David Gow]

On Sat, Jul 2, 2022 at 6:33 AM Luis Chamberlain <mcgrof@xxxxxxxxxx> wrote:
>
> On Fri, Jul 01, 2022 at 04:47:44PM +0800, David Gow wrote:
> > Make any kselftest test module (using the kselftest_module framework)
> > taint the kernel with TAINT_TEST on module load.
> >
> > Note that several selftests use kernel modules which are not based on
> > the kselftest_module framework, and so will not automatically taint the
> > kernel.
> >
> > This can be done in two ways:
> > - Moving the module to the tools/testing directory. All modules under
> >   this directory will taint the kernel.
> > - Adding the 'test' module property with:
> >   MODULE_INFO(test, "Y")
>
> This just needs to be documented somewhere other than a commit log.
> Otherwise I am not sure how we can be sure it will catch on.

I've updated the kselftest documentation for v5.

> > Similarly, selftests which do not load modules into the kernel generally
> > should not taint the kernel (or possibly should only do so on failure),
> > as it's assumed that testing from user-space should be safe. Regardless,
> > they can write to /proc/sys/kernel/tainted if required.
> >
> > Signed-off-by: David Gow <davidgow@xxxxxxxxxx>
>
> Looks good otherwise!
>
> Reviewed-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
>
> Do we want this to go through selftest / kunit / modules tree?
> Happy for it to through any. I can't predict a conflict.

I don't mind which tree it goes through either -- I'm not aware of
anything which would depend on it. I do have it on the list of things
pending for the KUnit tree, but it's much less KUnit-specific now
compared to v1. Regardless, I'll leave in the KUnit to-do list, and
we'll pick it up if no-one else particularly wants to.

Cheers,
-- David