[LTP] [PATCH 2/4] lib: Add .modprobe

[Edward Liaw]

Hi Petr,

On Fri, Nov 3, 2023 at 8:54 AM Petr Vorel <pvorel@suse.cz> wrote:
>
> > Hi!
> > > >   if (tst_test->mount_device)
> > > >           tst_test->format_device = 1;
>
> > > > @@ -1362,6 +1402,19 @@ static void do_cleanup(void)
>
> > > >   tst_sys_conf_restore(0);
>
> > > > + if (tst_test->modprobe) {
> > > > +         const char *name;
> > > > +         int i;
> > > > +
> > > > +         for (i = 0; (name = tst_test->modprobe[i]); ++i) {
> > > > +                 if (!modules_loaded[i])
> > > > +                         continue;
> > > > +
> > > > +                 const char *const cmd_rmmod[] = {"rmmod", name, NULL};
>
> > > modprobe -r please, rmmod has been deprecated for ages.
>
> > And one more minor point, we should attempt to remove the module only if
> > it has shown up in the /proc/modules.
>
> +1
>
> > Assuming that we want to skip the tst_module_is_buildin() check on some
> > systems as Ritchie suggested we would attempt to remove build in modules
> > here if we blindly trusted the return value from modpprobe.
>
> I guess for most of distros tst_check_builtin_driver() (which reads
> modules.builtin) makes sense. And with it we will have valid info if we should
> remove module or not.
>
> Then there is:
>
> 1) AOSP (Android), we should ask Edward what makes sense in Android.
> IMHO old AOSP versions used insmod and rmmod, but newer could support it [2].
> @Edward, am I correct? Also do AOSP even care about tests which use
> tst_module_unload()?

Android supports modprobe -r, but we're not currently running any of
the tests that use tst_module_unload because we're not building the
test modules.  I'll see if I can fix that, though.

>
> 2) NixOS
> This should be IMHO fixed by checking also the correct directory (ideally
> wrapped by some #ifdef, but can be even without it, if there is none).
>
> BTW, there is also /proc/sys/kernel/modules_disabled [1], I'm not sure if we
> want to just ignore it.
>
> Kind regards,
> Petr
>
> [1] https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
> [2] https://source.android.com/docs/core/architecture/kernel/loadable-kernel-modules