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

[David Gow]

On Sat, Jul 2, 2022 at 12:06 PM David Gow <davidgow@xxxxxxxxxx> wrote:
>
> 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.
>

FYI: It looks like patches 1 & 3 are already in the kunit tree, so it
makes sense to take the rest of them, too:
https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git/log/?h=kunit

Cheers,
-- David

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