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torvaldstorvalds
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Merge tag 'ratelimit.2025.07.23a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu
Pull ratelimit test updates from Paul McKenney: "Add functional and stress tests: - Add trivial kunit test for ratelimit - Make the ratelimit test more reliable (Petr Mladek) - Add stress test for ratelimit" * tag 'ratelimit.2025.07.23a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: lib: Add stress test for ratelimit lib: Make the ratelimit test more reliable lib: Add trivial kunit test for ratelimit
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‎lib/Kconfig.debug

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@@ -3214,6 +3214,17 @@ config TEST_OBJPOOL
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If unsure, say N.
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config RATELIMIT_KUNIT_TEST
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tristate "KUnit Test for correctness and stress of ratelimit" if !KUNIT_ALL_TESTS
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depends on KUNIT
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default KUNIT_ALL_TESTS
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help
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This builds the "test_ratelimit" module that should be used
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for correctness verification and concurrent testings of rate
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limiting.
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If unsure, say N.
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config INT_POW_KUNIT_TEST
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tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS
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depends on KUNIT

‎lib/tests/Makefile

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@@ -46,5 +46,6 @@ obj-$(CONFIG_STRING_KUNIT_TEST) += string_kunit.o
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obj-$(CONFIG_STRING_HELPERS_KUNIT_TEST) += string_helpers_kunit.o
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obj-$(CONFIG_USERCOPY_KUNIT_TEST) += usercopy_kunit.o
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obj-$(CONFIG_UTIL_MACROS_KUNIT) += util_macros_kunit.o
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obj-$(CONFIG_RATELIMIT_KUNIT_TEST) += test_ratelimit.o
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obj-$(CONFIG_TEST_RUNTIME_MODULE) += module/

‎lib/tests/test_ratelimit.c

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// SPDX-License-Identifier: GPL-2.0-only
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#include <kunit/test.h>
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#include <linux/ratelimit.h>
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#include <linux/module.h>
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#include <linux/kthread.h>
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#include <linux/cpumask.h>
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/* a simple boot-time regression test */
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#define TESTRL_INTERVAL (5 * HZ)
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static DEFINE_RATELIMIT_STATE(testrl, TESTRL_INTERVAL, 3);
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#define test_ratelimited(test, expected) \
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KUNIT_ASSERT_EQ(test, ___ratelimit(&testrl, "test_ratelimit_smoke"), (expected))
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static void test_ratelimit_smoke(struct kunit *test)
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{
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// Check settings.
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KUNIT_ASSERT_GE(test, TESTRL_INTERVAL, 100);
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// Test normal operation.
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test_ratelimited(test, true);
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test_ratelimited(test, true);
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test_ratelimited(test, true);
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test_ratelimited(test, false);
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schedule_timeout_idle(TESTRL_INTERVAL / 2);
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test_ratelimited(test, false);
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schedule_timeout_idle(TESTRL_INTERVAL * 3 / 4);
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test_ratelimited(test, true);
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schedule_timeout_idle(2 * TESTRL_INTERVAL);
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test_ratelimited(test, true);
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test_ratelimited(test, true);
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schedule_timeout_idle(TESTRL_INTERVAL / 2 );
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test_ratelimited(test, true);
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schedule_timeout_idle(TESTRL_INTERVAL * 3 / 4);
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test_ratelimited(test, true);
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test_ratelimited(test, true);
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test_ratelimited(test, true);
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test_ratelimited(test, false);
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// Test disabling.
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testrl.burst = 0;
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test_ratelimited(test, false);
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testrl.burst = 2;
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testrl.interval = 0;
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test_ratelimited(test, true);
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test_ratelimited(test, true);
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test_ratelimited(test, true);
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test_ratelimited(test, true);
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test_ratelimited(test, true);
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test_ratelimited(test, true);
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test_ratelimited(test, true);
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// Testing re-enabling.
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testrl.interval = TESTRL_INTERVAL;
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test_ratelimited(test, true);
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test_ratelimited(test, true);
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test_ratelimited(test, false);
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test_ratelimited(test, false);
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}
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static struct ratelimit_state stressrl = RATELIMIT_STATE_INIT_FLAGS("stressrl", HZ / 10, 3,
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RATELIMIT_MSG_ON_RELEASE);
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static int doneflag;
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static const int stress_duration = 2 * HZ;
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struct stress_kthread {
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unsigned long nattempts;
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unsigned long nunlimited;
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unsigned long nlimited;
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unsigned long nmissed;
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struct task_struct *tp;
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};
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static int test_ratelimit_stress_child(void *arg)
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{
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struct stress_kthread *sktp = arg;
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set_user_nice(current, MAX_NICE);
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WARN_ON_ONCE(!sktp->tp);
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while (!READ_ONCE(doneflag)) {
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sktp->nattempts++;
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if (___ratelimit(&stressrl, __func__))
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sktp->nunlimited++;
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else
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sktp->nlimited++;
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cond_resched();
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}
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sktp->nmissed = ratelimit_state_reset_miss(&stressrl);
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return 0;
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}
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static void test_ratelimit_stress(struct kunit *test)
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{
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int i;
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const int n_stress_kthread = cpumask_weight(cpu_online_mask);
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struct stress_kthread skt = { 0 };
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struct stress_kthread *sktp = kcalloc(n_stress_kthread, sizeof(*sktp), GFP_KERNEL);
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KUNIT_EXPECT_NOT_NULL_MSG(test, sktp, "Memory allocation failure");
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for (i = 0; i < n_stress_kthread; i++) {
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sktp[i].tp = kthread_run(test_ratelimit_stress_child, &sktp[i], "%s/%i",
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"test_ratelimit_stress_child", i);
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KUNIT_EXPECT_NOT_NULL_MSG(test, sktp, "kthread creation failure");
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pr_alert("Spawned test_ratelimit_stress_child %d\n", i);
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}
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schedule_timeout_idle(stress_duration);
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WRITE_ONCE(doneflag, 1);
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for (i = 0; i < n_stress_kthread; i++) {
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kthread_stop(sktp[i].tp);
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skt.nattempts += sktp[i].nattempts;
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skt.nunlimited += sktp[i].nunlimited;
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skt.nlimited += sktp[i].nlimited;
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skt.nmissed += sktp[i].nmissed;
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}
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KUNIT_ASSERT_EQ_MSG(test, skt.nunlimited + skt.nlimited, skt.nattempts,
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"Outcomes not equal to attempts");
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KUNIT_ASSERT_EQ_MSG(test, skt.nlimited, skt.nmissed, "Misses not equal to limits");
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}
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static struct kunit_case ratelimit_test_cases[] = {
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KUNIT_CASE_SLOW(test_ratelimit_smoke),
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KUNIT_CASE_SLOW(test_ratelimit_stress),
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{}
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};
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static struct kunit_suite ratelimit_test_suite = {
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.name = "lib_ratelimit",
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.test_cases = ratelimit_test_cases,
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};
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kunit_test_suites(&ratelimit_test_suite);
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MODULE_DESCRIPTION("___ratelimit() KUnit test suite");
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MODULE_LICENSE("GPL");

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