On Tue 2025-07-08 16:48:47, Arnd Bergmann wrote:
> On Tue, Jul 8, 2025, at 16:24, Petr Mladek wrote:
> > On Wed 2025-07-02 13:28:35, Nathan Chancellor wrote:
> >> On Wed, Jul 02, 2025 at 11:51:56AM +0200, Petr Mladek wrote:
> >
> > Thanks a lot for the nice report.
> >
> > The problem is how cpumask_var_t is defined in
> > include/linux/cpumask_types.h:
> >
> > #ifdef CONFIG_CPUMASK_OFFSTACK
> > typedef struct cpumask *cpumask_var_t;
> > #else
> > typedef struct cpumask cpumask_var_t[1];
> > #endif /* CONFIG_CPUMASK_OFFSTACK */
> >
> > And KUNIT_DEFINE_ACTION_WRAPPER() expect that the 3rd parameter
> > is a pointer.
> >
> > I am going to solve this by adding a wrapper over free_cpumask_var()
> > which would work with a pointer to cpumask_var_t.
>
> I'm not familiar enough with the cleanup mechanism of kunit,
> but can't you just move the mask allocation outside of
> test_readerwriter()?
The only solution would be global variable.
test_readerwriter() is the top-level function passed
to KUnit framework via:
KUNIT_CASE_SLOW(test_readerwriter),
And it seems that the clean is even done in a separate process.
I see the following:
KUNIT_CASE_SLOW() sets .run_case()
The callback is called via via:
+ kunit_try_run_case()
+ kunit_run_case_internal()
+ test_case->run_case()
And kunit_try_run_case() is called via:
+ kunit_run_case_catch_errors()
+ kunit_try_catch_run()
+ kthread_create()
-> kunit_try_run_case() in the new thread
The clean up is called from the same kunit_run_case_catch_errors()
in another thread
+ kunit_try_catch_run()
+ kthread_create()
-> kunit_try_run_case_cleanup() in another new thread
> > + */
> > +static void prbtest_free_cpumask_var(cpumask_var_t *mask)
> > +{
> > + free_cpumask_var(*mask);
> > +}
>
> Or you could pass this as a cpumask_t pointer instead,
> which should do the right thing without the indirection.
Nice trick. I am going to try it.
> > KUNIT_ASSERT_TRUE(test, alloc_cpumask_var(&test_cpus, GFP_KERNEL));
> > - err = kunit_add_action_or_reset(test, prbtest_cpumask_cleanup,
> > test_cpus);
> > + err = kunit_add_action_or_reset(test, prbtest_cpumask_cleanup,
> > &test_cpus);
>
> In my original version, I did not have the
> KUNIT_ASSERT_TRUE() here, which seems sufficient since this
> is not what you are testing at all, and in normal systems
> this would just be a stack variable.
I think that KUNIT_ASSERT is standard handling of any problem in the
test. At least, I see KUNIT_ASSERT*() after any *malloc*() in
the code samples in Documentation/dev-tools/kunit/usage.rst
Best Regards,
Petr
