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-rw-r--r--kernel/locking/test-ww_mutex.c646
1 files changed, 646 insertions, 0 deletions
diff --git a/kernel/locking/test-ww_mutex.c b/kernel/locking/test-ww_mutex.c
new file mode 100644
index 000000000000..da6c9a34f62f
--- /dev/null
+++ b/kernel/locking/test-ww_mutex.c
@@ -0,0 +1,646 @@
+/*
+ * Module-based API test facility for ww_mutexes
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
+ */
+
+#include <linux/kernel.h>
+
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/ww_mutex.h>
+
+static DEFINE_WW_CLASS(ww_class);
+struct workqueue_struct *wq;
+
+struct test_mutex {
+ struct work_struct work;
+ struct ww_mutex mutex;
+ struct completion ready, go, done;
+ unsigned int flags;
+};
+
+#define TEST_MTX_SPIN BIT(0)
+#define TEST_MTX_TRY BIT(1)
+#define TEST_MTX_CTX BIT(2)
+#define __TEST_MTX_LAST BIT(3)
+
+static void test_mutex_work(struct work_struct *work)
+{
+ struct test_mutex *mtx = container_of(work, typeof(*mtx), work);
+
+ complete(&mtx->ready);
+ wait_for_completion(&mtx->go);
+
+ if (mtx->flags & TEST_MTX_TRY) {
+ while (!ww_mutex_trylock(&mtx->mutex))
+ cpu_relax();
+ } else {
+ ww_mutex_lock(&mtx->mutex, NULL);
+ }
+ complete(&mtx->done);
+ ww_mutex_unlock(&mtx->mutex);
+}
+
+static int __test_mutex(unsigned int flags)
+{
+#define TIMEOUT (HZ / 16)
+ struct test_mutex mtx;
+ struct ww_acquire_ctx ctx;
+ int ret;
+
+ ww_mutex_init(&mtx.mutex, &ww_class);
+ ww_acquire_init(&ctx, &ww_class);
+
+ INIT_WORK_ONSTACK(&mtx.work, test_mutex_work);
+ init_completion(&mtx.ready);
+ init_completion(&mtx.go);
+ init_completion(&mtx.done);
+ mtx.flags = flags;
+
+ schedule_work(&mtx.work);
+
+ wait_for_completion(&mtx.ready);
+ ww_mutex_lock(&mtx.mutex, (flags & TEST_MTX_CTX) ? &ctx : NULL);
+ complete(&mtx.go);
+ if (flags & TEST_MTX_SPIN) {
+ unsigned long timeout = jiffies + TIMEOUT;
+
+ ret = 0;
+ do {
+ if (completion_done(&mtx.done)) {
+ ret = -EINVAL;
+ break;
+ }
+ cpu_relax();
+ } while (time_before(jiffies, timeout));
+ } else {
+ ret = wait_for_completion_timeout(&mtx.done, TIMEOUT);
+ }
+ ww_mutex_unlock(&mtx.mutex);
+ ww_acquire_fini(&ctx);
+
+ if (ret) {
+ pr_err("%s(flags=%x): mutual exclusion failure\n",
+ __func__, flags);
+ ret = -EINVAL;
+ }
+
+ flush_work(&mtx.work);
+ destroy_work_on_stack(&mtx.work);
+ return ret;
+#undef TIMEOUT
+}
+
+static int test_mutex(void)
+{
+ int ret;
+ int i;
+
+ for (i = 0; i < __TEST_MTX_LAST; i++) {
+ ret = __test_mutex(i);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int test_aa(void)
+{
+ struct ww_mutex mutex;
+ struct ww_acquire_ctx ctx;
+ int ret;
+
+ ww_mutex_init(&mutex, &ww_class);
+ ww_acquire_init(&ctx, &ww_class);
+
+ ww_mutex_lock(&mutex, &ctx);
+
+ if (ww_mutex_trylock(&mutex)) {
+ pr_err("%s: trylocked itself!\n", __func__);
+ ww_mutex_unlock(&mutex);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = ww_mutex_lock(&mutex, &ctx);
+ if (ret != -EALREADY) {
+ pr_err("%s: missed deadlock for recursing, ret=%d\n",
+ __func__, ret);
+ if (!ret)
+ ww_mutex_unlock(&mutex);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = 0;
+out:
+ ww_mutex_unlock(&mutex);
+ ww_acquire_fini(&ctx);
+ return ret;
+}
+
+struct test_abba {
+ struct work_struct work;
+ struct ww_mutex a_mutex;
+ struct ww_mutex b_mutex;
+ struct completion a_ready;
+ struct completion b_ready;
+ bool resolve;
+ int result;
+};
+
+static void test_abba_work(struct work_struct *work)
+{
+ struct test_abba *abba = container_of(work, typeof(*abba), work);
+ struct ww_acquire_ctx ctx;
+ int err;
+
+ ww_acquire_init(&ctx, &ww_class);
+ ww_mutex_lock(&abba->b_mutex, &ctx);
+
+ complete(&abba->b_ready);
+ wait_for_completion(&abba->a_ready);
+
+ err = ww_mutex_lock(&abba->a_mutex, &ctx);
+ if (abba->resolve && err == -EDEADLK) {
+ ww_mutex_unlock(&abba->b_mutex);
+ ww_mutex_lock_slow(&abba->a_mutex, &ctx);
+ err = ww_mutex_lock(&abba->b_mutex, &ctx);
+ }
+
+ if (!err)
+ ww_mutex_unlock(&abba->a_mutex);
+ ww_mutex_unlock(&abba->b_mutex);
+ ww_acquire_fini(&ctx);
+
+ abba->result = err;
+}
+
+static int test_abba(bool resolve)
+{
+ struct test_abba abba;
+ struct ww_acquire_ctx ctx;
+ int err, ret;
+
+ ww_mutex_init(&abba.a_mutex, &ww_class);
+ ww_mutex_init(&abba.b_mutex, &ww_class);
+ INIT_WORK_ONSTACK(&abba.work, test_abba_work);
+ init_completion(&abba.a_ready);
+ init_completion(&abba.b_ready);
+ abba.resolve = resolve;
+
+ schedule_work(&abba.work);
+
+ ww_acquire_init(&ctx, &ww_class);
+ ww_mutex_lock(&abba.a_mutex, &ctx);
+
+ complete(&abba.a_ready);
+ wait_for_completion(&abba.b_ready);
+
+ err = ww_mutex_lock(&abba.b_mutex, &ctx);
+ if (resolve && err == -EDEADLK) {
+ ww_mutex_unlock(&abba.a_mutex);
+ ww_mutex_lock_slow(&abba.b_mutex, &ctx);
+ err = ww_mutex_lock(&abba.a_mutex, &ctx);
+ }
+
+ if (!err)
+ ww_mutex_unlock(&abba.b_mutex);
+ ww_mutex_unlock(&abba.a_mutex);
+ ww_acquire_fini(&ctx);
+
+ flush_work(&abba.work);
+ destroy_work_on_stack(&abba.work);
+
+ ret = 0;
+ if (resolve) {
+ if (err || abba.result) {
+ pr_err("%s: failed to resolve ABBA deadlock, A err=%d, B err=%d\n",
+ __func__, err, abba.result);
+ ret = -EINVAL;
+ }
+ } else {
+ if (err != -EDEADLK && abba.result != -EDEADLK) {
+ pr_err("%s: missed ABBA deadlock, A err=%d, B err=%d\n",
+ __func__, err, abba.result);
+ ret = -EINVAL;
+ }
+ }
+ return ret;
+}
+
+struct test_cycle {
+ struct work_struct work;
+ struct ww_mutex a_mutex;
+ struct ww_mutex *b_mutex;
+ struct completion *a_signal;
+ struct completion b_signal;
+ int result;
+};
+
+static void test_cycle_work(struct work_struct *work)
+{
+ struct test_cycle *cycle = container_of(work, typeof(*cycle), work);
+ struct ww_acquire_ctx ctx;
+ int err;
+
+ ww_acquire_init(&ctx, &ww_class);
+ ww_mutex_lock(&cycle->a_mutex, &ctx);
+
+ complete(cycle->a_signal);
+ wait_for_completion(&cycle->b_signal);
+
+ err = ww_mutex_lock(cycle->b_mutex, &ctx);
+ if (err == -EDEADLK) {
+ ww_mutex_unlock(&cycle->a_mutex);
+ ww_mutex_lock_slow(cycle->b_mutex, &ctx);
+ err = ww_mutex_lock(&cycle->a_mutex, &ctx);
+ }
+
+ if (!err)
+ ww_mutex_unlock(cycle->b_mutex);
+ ww_mutex_unlock(&cycle->a_mutex);
+ ww_acquire_fini(&ctx);
+
+ cycle->result = err;
+}
+
+static int __test_cycle(unsigned int nthreads)
+{
+ struct test_cycle *cycles;
+ unsigned int n, last = nthreads - 1;
+ int ret;
+
+ cycles = kmalloc_array(nthreads, sizeof(*cycles), GFP_KERNEL);
+ if (!cycles)
+ return -ENOMEM;
+
+ for (n = 0; n < nthreads; n++) {
+ struct test_cycle *cycle = &cycles[n];
+
+ ww_mutex_init(&cycle->a_mutex, &ww_class);
+ if (n == last)
+ cycle->b_mutex = &cycles[0].a_mutex;
+ else
+ cycle->b_mutex = &cycles[n + 1].a_mutex;
+
+ if (n == 0)
+ cycle->a_signal = &cycles[last].b_signal;
+ else
+ cycle->a_signal = &cycles[n - 1].b_signal;
+ init_completion(&cycle->b_signal);
+
+ INIT_WORK(&cycle->work, test_cycle_work);
+ cycle->result = 0;
+ }
+
+ for (n = 0; n < nthreads; n++)
+ queue_work(wq, &cycles[n].work);
+
+ flush_workqueue(wq);
+
+ ret = 0;
+ for (n = 0; n < nthreads; n++) {
+ struct test_cycle *cycle = &cycles[n];
+
+ if (!cycle->result)
+ continue;
+
+ pr_err("cylic deadlock not resolved, ret[%d/%d] = %d\n",
+ n, nthreads, cycle->result);
+ ret = -EINVAL;
+ break;
+ }
+
+ for (n = 0; n < nthreads; n++)
+ ww_mutex_destroy(&cycles[n].a_mutex);
+ kfree(cycles);
+ return ret;
+}
+
+static int test_cycle(unsigned int ncpus)
+{
+ unsigned int n;
+ int ret;
+
+ for (n = 2; n <= ncpus + 1; n++) {
+ ret = __test_cycle(n);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+struct stress {
+ struct work_struct work;
+ struct ww_mutex *locks;
+ int nlocks;
+ int nloops;
+};
+
+static int *get_random_order(int count)
+{
+ int *order;
+ int n, r, tmp;
+
+ order = kmalloc_array(count, sizeof(*order), GFP_TEMPORARY);
+ if (!order)
+ return order;
+
+ for (n = 0; n < count; n++)
+ order[n] = n;
+
+ for (n = count - 1; n > 1; n--) {
+ r = get_random_int() % (n + 1);
+ if (r != n) {
+ tmp = order[n];
+ order[n] = order[r];
+ order[r] = tmp;
+ }
+ }
+
+ return order;
+}
+
+static void dummy_load(struct stress *stress)
+{
+ usleep_range(1000, 2000);
+}
+
+static void stress_inorder_work(struct work_struct *work)
+{
+ struct stress *stress = container_of(work, typeof(*stress), work);
+ const int nlocks = stress->nlocks;
+ struct ww_mutex *locks = stress->locks;
+ struct ww_acquire_ctx ctx;
+ int *order;
+
+ order = get_random_order(nlocks);
+ if (!order)
+ return;
+
+ ww_acquire_init(&ctx, &ww_class);
+
+ do {
+ int contended = -1;
+ int n, err;
+
+retry:
+ err = 0;
+ for (n = 0; n < nlocks; n++) {
+ if (n == contended)
+ continue;
+
+ err = ww_mutex_lock(&locks[order[n]], &ctx);
+ if (err < 0)
+ break;
+ }
+ if (!err)
+ dummy_load(stress);
+
+ if (contended > n)
+ ww_mutex_unlock(&locks[order[contended]]);
+ contended = n;
+ while (n--)
+ ww_mutex_unlock(&locks[order[n]]);
+
+ if (err == -EDEADLK) {
+ ww_mutex_lock_slow(&locks[order[contended]], &ctx);
+ goto retry;
+ }
+
+ if (err) {
+ pr_err_once("stress (%s) failed with %d\n",
+ __func__, err);
+ break;
+ }
+ } while (--stress->nloops);
+
+ ww_acquire_fini(&ctx);
+
+ kfree(order);
+ kfree(stress);
+}
+
+struct reorder_lock {
+ struct list_head link;
+ struct ww_mutex *lock;
+};
+
+static void stress_reorder_work(struct work_struct *work)
+{
+ struct stress *stress = container_of(work, typeof(*stress), work);
+ LIST_HEAD(locks);
+ struct ww_acquire_ctx ctx;
+ struct reorder_lock *ll, *ln;
+ int *order;
+ int n, err;
+
+ order = get_random_order(stress->nlocks);
+ if (!order)
+ return;
+
+ for (n = 0; n < stress->nlocks; n++) {
+ ll = kmalloc(sizeof(*ll), GFP_KERNEL);
+ if (!ll)
+ goto out;
+
+ ll->lock = &stress->locks[order[n]];
+ list_add(&ll->link, &locks);
+ }
+ kfree(order);
+ order = NULL;
+
+ ww_acquire_init(&ctx, &ww_class);
+
+ do {
+ list_for_each_entry(ll, &locks, link) {
+ err = ww_mutex_lock(ll->lock, &ctx);
+ if (!err)
+ continue;
+
+ ln = ll;
+ list_for_each_entry_continue_reverse(ln, &locks, link)
+ ww_mutex_unlock(ln->lock);
+
+ if (err != -EDEADLK) {
+ pr_err_once("stress (%s) failed with %d\n",
+ __func__, err);
+ break;
+ }
+
+ ww_mutex_lock_slow(ll->lock, &ctx);
+ list_move(&ll->link, &locks); /* restarts iteration */
+ }
+
+ dummy_load(stress);
+ list_for_each_entry(ll, &locks, link)
+ ww_mutex_unlock(ll->lock);
+ } while (--stress->nloops);
+
+ ww_acquire_fini(&ctx);
+
+out:
+ list_for_each_entry_safe(ll, ln, &locks, link)
+ kfree(ll);
+ kfree(order);
+ kfree(stress);
+}
+
+static void stress_one_work(struct work_struct *work)
+{
+ struct stress *stress = container_of(work, typeof(*stress), work);
+ const int nlocks = stress->nlocks;
+ struct ww_mutex *lock = stress->locks + (get_random_int() % nlocks);
+ int err;
+
+ do {
+ err = ww_mutex_lock(lock, NULL);
+ if (!err) {
+ dummy_load(stress);
+ ww_mutex_unlock(lock);
+ } else {
+ pr_err_once("stress (%s) failed with %d\n",
+ __func__, err);
+ break;
+ }
+ } while (--stress->nloops);
+
+ kfree(stress);
+}
+
+#define STRESS_INORDER BIT(0)
+#define STRESS_REORDER BIT(1)
+#define STRESS_ONE BIT(2)
+#define STRESS_ALL (STRESS_INORDER | STRESS_REORDER | STRESS_ONE)
+
+static int stress(int nlocks, int nthreads, int nloops, unsigned int flags)
+{
+ struct ww_mutex *locks;
+ int n;
+
+ locks = kmalloc_array(nlocks, sizeof(*locks), GFP_KERNEL);
+ if (!locks)
+ return -ENOMEM;
+
+ for (n = 0; n < nlocks; n++)
+ ww_mutex_init(&locks[n], &ww_class);
+
+ for (n = 0; nthreads; n++) {
+ struct stress *stress;
+ void (*fn)(struct work_struct *work);
+
+ fn = NULL;
+ switch (n & 3) {
+ case 0:
+ if (flags & STRESS_INORDER)
+ fn = stress_inorder_work;
+ break;
+ case 1:
+ if (flags & STRESS_REORDER)
+ fn = stress_reorder_work;
+ break;
+ case 2:
+ if (flags & STRESS_ONE)
+ fn = stress_one_work;
+ break;
+ }
+
+ if (!fn)
+ continue;
+
+ stress = kmalloc(sizeof(*stress), GFP_KERNEL);
+ if (!stress)
+ break;
+
+ INIT_WORK(&stress->work, fn);
+ stress->locks = locks;
+ stress->nlocks = nlocks;
+ stress->nloops = nloops;
+
+ queue_work(wq, &stress->work);
+ nthreads--;
+ }
+
+ flush_workqueue(wq);
+
+ for (n = 0; n < nlocks; n++)
+ ww_mutex_destroy(&locks[n]);
+ kfree(locks);
+
+ return 0;
+}
+
+static int __init test_ww_mutex_init(void)
+{
+ int ncpus = num_online_cpus();
+ int ret;
+
+ wq = alloc_workqueue("test-ww_mutex", WQ_UNBOUND, 0);
+ if (!wq)
+ return -ENOMEM;
+
+ ret = test_mutex();
+ if (ret)
+ return ret;
+
+ ret = test_aa();
+ if (ret)
+ return ret;
+
+ ret = test_abba(false);
+ if (ret)
+ return ret;
+
+ ret = test_abba(true);
+ if (ret)
+ return ret;
+
+ ret = test_cycle(ncpus);
+ if (ret)
+ return ret;
+
+ ret = stress(16, 2*ncpus, 1<<10, STRESS_INORDER);
+ if (ret)
+ return ret;
+
+ ret = stress(16, 2*ncpus, 1<<10, STRESS_REORDER);
+ if (ret)
+ return ret;
+
+ ret = stress(4096, hweight32(STRESS_ALL)*ncpus, 1<<12, STRESS_ALL);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static void __exit test_ww_mutex_exit(void)
+{
+ destroy_workqueue(wq);
+}
+
+module_init(test_ww_mutex_init);
+module_exit(test_ww_mutex_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Intel Corporation");
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-12-20 09:46:18 +0000