Re: [PATCH] irq: Make refcount_interrupt kunit test selectable

On Sun, Aug 23, 2026 at 05:52:24PM -0400, Radu Rendec wrote:
> On Sun, 2026-08-23 at 14:08 -0700, Boqun Feng wrote:
> > On Sun, Aug 23, 2026 at 04:46:23PM -0400, Radu Rendec wrote:
> > > On Sun, 2026-08-23 at 17:17 +0000, Kuan-Wei Chiu wrote:
> > > > Currently, refcount_interrupt_test is built unconditionally when
> > > > CONFIG_KUNIT is enabled, causing it to run unexpectedly during boot.
> > > > 
> > > > Fix this by introducing CONFIG_REFCOUNT_INTERRUPT_KUNIT_TEST so the
> > > > test can be configured independently, following standard kunit
> > > > practices.
> > > > 
> > > > Fixes: 07a88e2bcd5b ("irq: Add KUnit test for refcounted interrupt enable/disable")
> > > > Signed-off-by: Kuan-Wei Chiu <[email protected]>
> > > > ---
> > > >  kernel/irq/Kconfig  | 12 ++++++++++++
> > > >  kernel/irq/Makefile |  2 +-
> > > >  2 files changed, 13 insertions(+), 1 deletion(-)
> > > 
> > > Can someone please explain me why this needs to be a separate unit test
> > > in the first place and can't be integrated into the (previously)
> > > existing unit test gated by IRQ_KUNIT_TEST?
> > > 
> > 
> > If you look at the irq_test.c, you will find that it primarily tests the
> > {request,disable,enable}_irq() API (i.e. allocating IRQ vectors and
> > enabling and disabling them), which is not the same scope as
> > local_interrupt_{disable,enable}() (i.e. operating the CPU irq disabling
> > status), so it makes sense to have a separate test case.
> 
> Thanks! If we want to keep the unit tests separated/grouped by scope,
> then yes, it makes sense for sure. What I don't like about this is:
>  * The naming of the two config options is inconsistent: IRQ_KUNIT_TEST
>    and REFCOUNT_INTERRUPT_KUNIT_TEST.
>  * The naming and description of the older test become misleading. The
>    way they are formulated, I would expect them to test "everything
>    related to IRQ" but now we have a separate option (and kunit test)
>    dedicated to the refcount stuff.
> 

These are valid points. However, I think the "inconsistency" comes from
refcount_interrupt_test.c being in kernel/irq/. IRQ management (code in
kernel/irq/) and IRQ disabling/enabling are very different things to me
(for example include/linux/irqflags.h is not listed in the "IRQ
SUBSYSTEM" entry). IMO, refcount_interrupt_test.c should be moved into
lib/tests/.

> If they must be separated/grouped by scope, I would find it much nicer
> and less confusing if they were called something like:
> IRQ_MANAGEMENT_KUNIT_TEST and
> IRQ_REFCOUNT_KUNIT_TEST,
> and also the corresponding .c files were somewhat consistent with the
> Kconfig option names. The description of the older test would have to
> be updated to make it clear that it's not just "everything IRQ".
> 
> In that scenario, new kunit test(s) related to different aspects of the
> IRQ subsystem would get their own Kconfig option and file, and would
> hopefully follow the same naming pattern.
> 
> To be clear, I'm not arguing that keeping the tests separate is wrong.
> I'm arguing that if we do that, we should also make some adjustments to
> keep everything clean and tidy.
> 

Understood, and thank you for bringing it up. 

So how about we keep Kuan-Wei's fix as it is and move the
refcount_interrupt_test.c file into lib/tests/? It's more clean and tidy
to me this way. Thoughts?

Regards,
Boqun

> > But yes, I agree Kuan-Wei's fix is needed.
> 
> Yes, I agree, those unit tests must not be gated by KUNIT alone, so
> something must be done to fix it.
> 
> > > Ironically, both the issue that this patch is trying to fix and my
> > > question were raised by sashiko here:
> > > https://lore.kernel.org/all/[email protected]/
> > > 
> > > > diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
> > > > index 05cba4e16dad..6923f37eaab4 100644
> > > > --- a/kernel/irq/Kconfig
> > > > +++ b/kernel/irq/Kconfig
> > > > @@ -150,6 +150,18 @@ config IRQ_KUNIT_TEST
> > > >  
> > > >     If unsure, say N.
> > > >  
> > > > +config REFCOUNT_INTERRUPT_KUNIT_TEST
> > > > + tristate "Test refcounted interrupt enable/disable" if !KUNIT_ALL_TESTS
> > > > + depends on KUNIT
> > > > + default KUNIT_ALL_TESTS
> > > > + help
> > > > +   This builds the kunit tests for the refcounted interrupt
> > > > +   infrastructure. It verifies the correctness of single, nested,
> > > > +   and multiple interrupt enable/disable state changes and ensures
> > > > +   that the underlying reference counting mechanisms work as expected.
> > > > +
> > > > +   If unsure, say N.
> > > > +
> > > >  endmenu
> > > >  
> > > >  config GENERIC_IRQ_MULTI_HANDLER
> > > > diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile
> > > > index 44c4d6fc502a..0e5df962a149 100644
> > > > --- a/kernel/irq/Makefile
> > > > +++ b/kernel/irq/Makefile
> > > > @@ -16,4 +16,4 @@ obj-$(CONFIG_SMP) += affinity.o
> > > >  obj-$(CONFIG_GENERIC_IRQ_DEBUGFS) += debugfs.o
> > > >  obj-$(CONFIG_GENERIC_IRQ_MATRIX_ALLOCATOR) += matrix.o
> > > >  obj-$(CONFIG_IRQ_KUNIT_TEST) += irq_test.o
> > > > -obj-$(CONFIG_KUNIT) += refcount_interrupt_test.o
> > > > +obj-$(CONFIG_REFCOUNT_INTERRUPT_KUNIT_TEST) += refcount_interrupt_test.o
> 
> -- 
> Best regards,
> Radu