Re: [PATCH v3 4/4] rv/reactors: add KUnit tests for reactor registration and dispatch

[Gabriele Monaco <gmonaco@redhat.com>]

On Mon, 2026-08-10 at 01:10 +0800, wen.yang@linux.dev wrote:
> From: Wen Yang <wen.yang@linux.dev>
> 
> Add KUnit tests covering the reactor register/unregister lifecycle
> (including duplicate and name-length rejection) and rv_react() dispatch
> (a no-op without a callback, exactly one invocation with one; the mdelay
> callback keeps the CPU busy so a timer interrupt exercises the LD_WAIT_SPIN
> lockdep context).  The Kconfig entry is tristate so the tests can be built
> as a module when CONFIG_KUNIT=m; only RV_REACTORS is required.
> 

Looks simple and good now.

> Suggested-by: Gabriele Monaco <gmonaco@redhat.com>

Same as before, you can leave only

Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>

Thanks
Gabriele

> Signed-off-by: Wen Yang <wen.yang@linux.dev>
> ---
>  kernel/trace/rv/Kconfig             |  12 +++
>  kernel/trace/rv/Makefile            |   1 +
>  kernel/trace/rv/rv_reactors_kunit.c | 119 ++++++++++++++++++++++++++++
>  3 files changed, 132 insertions(+)
>  create mode 100644 kernel/trace/rv/rv_reactors_kunit.c
> 
> diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
> index efa930f94ea4..9bfd429ffdea 100644
> --- a/kernel/trace/rv/Kconfig
> +++ b/kernel/trace/rv/Kconfig
> @@ -113,6 +113,18 @@ config RV_REACT_PANIC
>  	  Enables the panic reactor. The panic reactor emits a printk()
>  	  message if an exception is found and panic()s the system.
>  
> +config RV_REACTORS_KUNIT
> +	tristate "KUnit tests for RV reactors" if !KUNIT_ALL_TESTS
> +	depends on KUNIT
> +	depends on RV_REACTORS
> +	default KUNIT_ALL_TESTS
> +	help
> +	  Enable KUnit tests for RV reactor registration and dispatch.
> +	  These tests verify the register/unregister lifecycle, duplicate
> +	  rejection, and that rv_react() correctly invokes callbacks.
> +
> +	  If unsure, say N.
> +
>  config RV_MONITORS_KUNIT_TEST
>  	tristate "KUnit tests for RV monitors" if !KUNIT_ALL_TESTS
>  	depends on KUNIT && RV && RV_REACTORS
> diff --git a/kernel/trace/rv/Makefile b/kernel/trace/rv/Makefile
> index cdbf68c84f5a..c895d81dfdad 100644
> --- a/kernel/trace/rv/Makefile
> +++ b/kernel/trace/rv/Makefile
> @@ -25,4 +25,5 @@ obj-$(CONFIG_RV_MON_WAKEUP) += monitors/wakeup/wakeup.o
>  obj-$(CONFIG_RV_REACTORS) += rv_reactors.o
>  obj-$(CONFIG_RV_REACT_PRINTK) += reactor_printk.o
>  obj-$(CONFIG_RV_REACT_PANIC) += reactor_panic.o
> +obj-$(CONFIG_RV_REACTORS_KUNIT) += rv_reactors_kunit.o
>  obj-$(CONFIG_RV_MONITORS_KUNIT_TEST) += rv_monitors_test.o
> diff --git a/kernel/trace/rv/rv_reactors_kunit.c
> b/kernel/trace/rv/rv_reactors_kunit.c
> new file mode 100644
> index 000000000000..d5b731eb11f3
> --- /dev/null
> +++ b/kernel/trace/rv/rv_reactors_kunit.c
> @@ -0,0 +1,119 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * KUnit tests for RV reactor registration and dispatch.
> + */
> +
> +#include <kunit/test.h>
> +#include <linux/rv.h>
> +#include <linux/delay.h>
> +#include <linux/atomic.h>
> +#include "rv.h"
> +
> +static struct rv_reactor test_reactor = {
> +	.name		= "kunit_test_reactor",
> +	.description	= "KUnit test reactor",
> +};
> +
> +static void reactor_teardown(void *arg)
> +{
> +	rv_unregister_reactor(&test_reactor);
> +}
> +
> +static void register_test_reactor(struct kunit *test)
> +{
> +	KUNIT_ASSERT_EQ(test, rv_register_reactor(&test_reactor), 0);
> +	KUNIT_ASSERT_EQ(test,
> +			kunit_add_action_or_reset(test, reactor_teardown,
> NULL), 0);
> +}
> +
> +static void test_double_register(struct kunit *test)
> +{
> +	register_test_reactor(test);
> +	KUNIT_EXPECT_EQ(test, rv_register_reactor(&test_reactor), -EINVAL);
> +}
> +
> +/*
> + * Use a fixed-size array so sizeof() gives the exact byte count at
> + * compile time.
> + */
> +static const char long_reactor_name[] = "kunit_reactor_name_too_long_xxx_";
> +_Static_assert(sizeof(long_reactor_name) - 1 >= MAX_RV_REACTOR_NAME_SIZE,
> +	       "long_reactor_name must be at least MAX_RV_REACTOR_NAME_SIZE
> chars");
> +
> +static void test_name_too_long(struct kunit *test)
> +{
> +	static struct rv_reactor long_reactor = {
> +		.name = long_reactor_name,
> +	};
> +
> +	KUNIT_EXPECT_EQ(test, rv_register_reactor(&long_reactor), -EINVAL);
> +}
> +
> +static struct kunit_case rv_reactor_registration_cases[] = {
> +	KUNIT_CASE(test_double_register),
> +	KUNIT_CASE(test_name_too_long),
> +	{}
> +};
> +
> +static struct kunit_suite rv_reactor_registration_suite = {
> +	.name		= "rv_reactor_registration",
> +	.test_cases	= rv_reactor_registration_cases,
> +};
> +
> +static atomic_t react_call_count;
> +
> +__printf(1, 0) static void mock_react(const char *msg, va_list args)
> +{
> +	atomic_inc(&react_call_count);
> +	/*
> +	 * Hold the CPU for 5 ms so a timer interrupt is likely to fire
> +	 * inside rv_react()'s lockdep context, exercising the LD_WAIT_SPIN
> +	 * constraint.  mdelay() is a calibrated busy-wait with no scheduler
> +	 * interaction.
> +	 */
> +	mdelay(5);
> +}
> +
> +static void test_react_no_callback(struct kunit *test)
> +{
> +	struct rv_monitor monitor = {
> +		.name = "kunit_null_react",
> +	};
> +
> +	atomic_set(&react_call_count, 0);
> +	rv_react(&monitor, "no callback");
> +
> +	/*
> +	 * The only possible failure in this test case is a kernel panic.
> +	 * NULL react guard: callback must NOT have been invoked
> +	 */
> +	KUNIT_EXPECT_EQ(test, atomic_read(&react_call_count), 0);
> +}
> +
> +static void test_react_callback_invoked(struct kunit *test)
> +{
> +	struct rv_monitor monitor = {
> +		.name	= "kunit_dispatch_monitor",
> +		.react	= mock_react,
> +	};
> +
> +	atomic_set(&react_call_count, 0);
> +	rv_react(&monitor, "callback invocation test");
> +	KUNIT_EXPECT_EQ(test, atomic_read(&react_call_count), 1);
> +}
> +
> +static struct kunit_case rv_react_dispatch_cases[] = {
> +	KUNIT_CASE(test_react_no_callback),
> +	KUNIT_CASE(test_react_callback_invoked),
> +	{}
> +};
> +
> +static struct kunit_suite rv_react_dispatch_suite = {
> +	.name		= "rv_react_dispatch",
> +	.test_cases	= rv_react_dispatch_cases,
> +};
> +
> +kunit_test_suites(&rv_reactor_registration_suite, &rv_react_dispatch_suite);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("KUnit tests for RV reactor registration and dispatch");