On Wed, Jul 02, 2025 at 11:51:56AM +0200, Petr Mladek wrote:
> From: Arnd Bergmann <a...@arndb.de>
>
> For large values of CONFIG_NR_CPUS, the newly added kunit test fails
> to build:
>
> kernel/printk/printk_ringbuffer_kunit_test.c: In function 'test_readerwriter':
> kernel/printk/printk_ringbuffer_kunit_test.c:279:1: error: the frame size of
> 1432 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]
>
> Change this to use cpumask_var_t and allocate it dynamically when
> CONFIG_CPUMASK_OFFSTACK is set.
>
> Fixes: 5ea2bcdfbf46 ("printk: ringbuffer: Add KUnit test")
> Signed-off-by: Arnd Bergmann <a...@arndb.de>
> [pmla...@suse.com: Correctly handle allocation failures and freeing using
> KUnit test API.]
> Signed-off-by: Petr Mladek <pmla...@suse.com>
> ---
> kernel/printk/printk_ringbuffer_kunit_test.c | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/kernel/printk/printk_ringbuffer_kunit_test.c
> b/kernel/printk/printk_ringbuffer_kunit_test.c
> index 217dcc14670c..0c3030fde8c2 100644
> --- a/kernel/printk/printk_ringbuffer_kunit_test.c
> +++ b/kernel/printk/printk_ringbuffer_kunit_test.c
> @@ -216,6 +216,7 @@ static int prbtest_reader(struct prbtest_data *test_data,
> unsigned long timeout_
> return 0;
> }
>
> +KUNIT_DEFINE_ACTION_WRAPPER(prbtest_cpumask_cleanup, free_cpumask_var,
> cpumask_var_t);
This appears to break the build for me when CONFIG_CPUMASK_OFFSTACK is not
set, like when enabling this test on top of x86_64 defconfig:
In file included from kernel/printk/printk_ringbuffer_kunit_test.c:14:
kernel/printk/printk_ringbuffer_kunit_test.c: In function
'prbtest_cpumask_cleanup':
include/kunit/resource.h:409:32: error: cast specifies array type
409 | arg_type arg = (arg_type)in; \
| ^
kernel/printk/printk_ringbuffer_kunit_test.c:226:1: note: in expansion of
macro 'KUNIT_DEFINE_ACTION_WRAPPER'
226 | KUNIT_DEFINE_ACTION_WRAPPER(prbtest_cpumask_cleanup,
free_cpumask_var, cpumask_var_t);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
Clang's error might be a little clearer with the "aka" note it provides.
kernel/printk/printk_ringbuffer_kunit_test.c:226:1: error: used type
'cpumask_var_t' (aka 'struct cpumask[1]') where arithmetic or pointer type is
required
226 | KUNIT_DEFINE_ACTION_WRAPPER(prbtest_cpumask_cleanup,
free_cpumask_var, cpumask_var_t);
|
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/kunit/resource.h:409:18: note: expanded from macro
'KUNIT_DEFINE_ACTION_WRAPPER'
409 | arg_type arg = (arg_type)in; \
| ^ ~~
> KUNIT_DEFINE_ACTION_WRAPPER(prbtest_kthread_cleanup, kthread_stop, struct
> task_struct *);
>
> static void prbtest_add_kthread_cleanup(struct kunit *test, struct
> task_struct *kthread)
> @@ -240,8 +241,13 @@ static void test_readerwriter(struct kunit *test)
> struct prbtest_thread_data *thread_data;
> struct prbtest_data *test_data;
> struct task_struct *thread;
> - cpumask_t test_cpus;
> + cpumask_var_t test_cpus;
> int cpu, reader_cpu;
> + int err;
> +
> + KUNIT_ASSERT_TRUE(test, alloc_cpumask_var(&test_cpus, GFP_KERNEL));
> + err = kunit_add_action_or_reset(test, prbtest_cpumask_cleanup,
> test_cpus);
> + KUNIT_ASSERT_EQ(test, err, 0);
>
> cpus_read_lock();
> /*
> @@ -250,15 +256,15 @@ static void test_readerwriter(struct kunit *test)
> * Instead use a snapshot of the online CPUs.
> * If they change during test execution it is unfortunate but not a
> grave error.
> */
> - cpumask_copy(&test_cpus, cpu_online_mask);
> + cpumask_copy(test_cpus, cpu_online_mask);
> cpus_read_unlock();
>
> /* One CPU is for the reader, all others are writers */
> - reader_cpu = cpumask_first(&test_cpus);
> - if (cpumask_weight(&test_cpus) == 1)
> + reader_cpu = cpumask_first(test_cpus);
> + if (cpumask_weight(test_cpus) == 1)
> kunit_warn(test, "more than one CPU is recommended");
> else
> - cpumask_clear_cpu(reader_cpu, &test_cpus);
> + cpumask_clear_cpu(reader_cpu, test_cpus);
>
> /* KUnit test can get restarted more times. */
> prbtest_prb_reinit(&test_rb);
> @@ -271,7 +277,7 @@ static void test_readerwriter(struct kunit *test)
>
> kunit_info(test, "running for %lu ms\n", runtime_ms);
>
> - for_each_cpu(cpu, &test_cpus) {
> + for_each_cpu(cpu, test_cpus) {
> thread_data = kunit_kmalloc(test, sizeof(*thread_data),
> GFP_KERNEL);
> KUNIT_ASSERT_NOT_NULL(test, thread_data);
> thread_data->test_data = test_data;
> --
> 2.50.0
>
