Commit bf42df09 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Petr Mladek
Browse files

printk: kunit: support offstack cpumask 



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.

The variable has to be released via a KUnit action wrapper so that it is
freed when the test fails and gets aborted. The parameter type is hardcoded
to "struct cpumask *" because the macro KUNIT_DEFINE_ACTION_WRAPPER()
does not accept an array. But the function does nothing when
CONFIG_CPUMASK_OFFSTACK is not set anyway.

Fixes: 5ea2bcdf ("printk: ringbuffer: Add KUnit test")
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/all/20250620192554.2234184-1-arnd@kernel.org # v1
[pmladek@suse.com: Correctly handle allocation failures and freeing using KUnit test API.]
Link: https://lore.kernel.org/all/20250702095157.110916-3-pmladek@suse.com

 # v2
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
parent d18d7989

kernel/printk/printk_ringbuffer_kunit_test.c

+18 −6
Original line number Diff line number Diff line
@@ -223,8 +223,17 @@ static int prbtest_reader(struct prbtest_data *test_data, unsigned long timeout_ 
	return 0;

}



KUNIT_DEFINE_ACTION_WRAPPER(prbtest_cpumask_cleanup, free_cpumask_var, struct cpumask *);

KUNIT_DEFINE_ACTION_WRAPPER(prbtest_kthread_cleanup, kthread_stop, struct task_struct *);



static void prbtest_add_cpumask_cleanup(struct kunit *test, cpumask_var_t mask)

{

	int err;



	err = kunit_add_action_or_reset(test, prbtest_cpumask_cleanup, mask);

	KUNIT_ASSERT_EQ(test, err, 0);

}



static void prbtest_add_kthread_cleanup(struct kunit *test, struct task_struct *kthread)

{

	int err;
@@ -247,9 +256,12 @@ 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;



	KUNIT_ASSERT_TRUE(test, alloc_cpumask_var(&test_cpus, GFP_KERNEL));

	prbtest_add_cpumask_cleanup(test, test_cpus);



	cpus_read_lock();

	/*

	 * Failure of KUNIT_ASSERT() kills the current task
@@ -257,15 +269,15 @@ 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);
@@ -278,7 +290,7 @@ 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;