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Message-ID: <20250902140326.344214-1-pmladek@suse.com>
Date: Tue, 2 Sep 2025 16:03:26 +0200
From: Petr Mladek <pmladek@...e.com>
To: Thomas Weißschuh <thomas.weissschuh@...utronix.de>,
John Ogness <john.ogness@...utronix.de>,
Arnd Bergmann <arnd@...db.de>,
Dan Carpenter <dan.carpenter@...aro.org>
Cc: Steven Rostedt <rostedt@...dmis.org>,
Sergey Senozhatsky <senozhatsky@...omium.org>,
Kees Cook <kees@...nel.org>,
"Gustavo A . R . Silva" <gustavoars@...nel.org>,
David Gow <davidgow@...gle.com>,
Arnd Bergmann <arnd@...nel.org>,
linux-kernel@...r.kernel.org,
linux-hardening@...r.kernel.org,
Petr Mladek <pmladek@...e.com>
Subject: [PATCH v3] printk: kunit: support offstack cpumask
From: Arnd Bergmann <arnd@...db.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.
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: 5ea2bcdfbf46 ("printk: ringbuffer: Add KUnit test")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
[pmladek@...e.com: Correctly handle allocation failures and freeing using KUnit test API.]
Signed-off-by: Petr Mladek <pmladek@...e.com>
---
This patch applies on top of "rework/ringbuffer-kunit-test" branch
in printk/linux.git.
Changes against v2 [2]:
- Hardcode the pointer type to "struct cpumask *" when defining
prbtest_cpumask_cleanup() action to avoid warning
when CONFIG_CPUMASK_OFFSTACK is not set.
Changes against v1 [1]:
- Abort the test when the cpumask allocation fails.
- Free the cpumask when the tests exits.
[1] https://lore.kernel.org/all/20250620192554.2234184-1-arnd@kernel.org
[2] https://lore.kernel.org/all/20250702095157.110916-3-pmladek@suse.com
kernel/printk/printk_ringbuffer_kunit_test.c | 24 +++++++++++++++-----
1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/kernel/printk/printk_ringbuffer_kunit_test.c b/kernel/printk/printk_ringbuffer_kunit_test.c
index e67e1815f4c8..2282348e869a 100644
--- a/kernel/printk/printk_ringbuffer_kunit_test.c
+++ b/kernel/printk/printk_ringbuffer_kunit_test.c
@@ -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;
--
2.50.1
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