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-rw-r--r--tools/testing/radix-tree/iteration_check.c210
1 files changed, 210 insertions, 0 deletions
diff --git a/tools/testing/radix-tree/iteration_check.c b/tools/testing/radix-tree/iteration_check.c
new file mode 100644
index 0000000000..e9908bcb06
--- /dev/null
+++ b/tools/testing/radix-tree/iteration_check.c
@@ -0,0 +1,210 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * iteration_check.c: test races having to do with xarray iteration
+ * Copyright (c) 2016 Intel Corporation
+ * Author: Ross Zwisler <ross.zwisler@linux.intel.com>
+ */
+#include <pthread.h>
+#include "test.h"
+
+#define NUM_THREADS 5
+#define MAX_IDX 100
+#define TAG XA_MARK_0
+#define NEW_TAG XA_MARK_1
+
+static pthread_t threads[NUM_THREADS];
+static unsigned int seeds[3];
+static DEFINE_XARRAY(array);
+static bool test_complete;
+static int max_order;
+
+void my_item_insert(struct xarray *xa, unsigned long index)
+{
+ XA_STATE(xas, xa, index);
+ struct item *item = item_create(index, 0);
+ int order;
+
+retry:
+ xas_lock(&xas);
+ for (order = max_order; order >= 0; order--) {
+ xas_set_order(&xas, index, order);
+ item->order = order;
+ if (xas_find_conflict(&xas))
+ continue;
+ xas_store(&xas, item);
+ xas_set_mark(&xas, TAG);
+ break;
+ }
+ xas_unlock(&xas);
+ if (xas_nomem(&xas, GFP_KERNEL))
+ goto retry;
+ if (order < 0)
+ free(item);
+}
+
+/* relentlessly fill the array with tagged entries */
+static void *add_entries_fn(void *arg)
+{
+ rcu_register_thread();
+
+ while (!test_complete) {
+ unsigned long pgoff;
+
+ for (pgoff = 0; pgoff < MAX_IDX; pgoff++) {
+ my_item_insert(&array, pgoff);
+ }
+ }
+
+ rcu_unregister_thread();
+
+ return NULL;
+}
+
+/*
+ * Iterate over tagged entries, retrying when we find ourselves in a deleted
+ * node and randomly pausing the iteration.
+ */
+static void *tagged_iteration_fn(void *arg)
+{
+ XA_STATE(xas, &array, 0);
+ void *entry;
+
+ rcu_register_thread();
+
+ while (!test_complete) {
+ xas_set(&xas, 0);
+ rcu_read_lock();
+ xas_for_each_marked(&xas, entry, ULONG_MAX, TAG) {
+ if (xas_retry(&xas, entry))
+ continue;
+
+ if (rand_r(&seeds[0]) % 50 == 0) {
+ xas_pause(&xas);
+ rcu_read_unlock();
+ rcu_barrier();
+ rcu_read_lock();
+ }
+ }
+ rcu_read_unlock();
+ }
+
+ rcu_unregister_thread();
+
+ return NULL;
+}
+
+/*
+ * Iterate over the entries, retrying when we find ourselves in a deleted
+ * node and randomly pausing the iteration.
+ */
+static void *untagged_iteration_fn(void *arg)
+{
+ XA_STATE(xas, &array, 0);
+ void *entry;
+
+ rcu_register_thread();
+
+ while (!test_complete) {
+ xas_set(&xas, 0);
+ rcu_read_lock();
+ xas_for_each(&xas, entry, ULONG_MAX) {
+ if (xas_retry(&xas, entry))
+ continue;
+
+ if (rand_r(&seeds[1]) % 50 == 0) {
+ xas_pause(&xas);
+ rcu_read_unlock();
+ rcu_barrier();
+ rcu_read_lock();
+ }
+ }
+ rcu_read_unlock();
+ }
+
+ rcu_unregister_thread();
+
+ return NULL;
+}
+
+/*
+ * Randomly remove entries to help induce retries in the
+ * two iteration functions.
+ */
+static void *remove_entries_fn(void *arg)
+{
+ rcu_register_thread();
+
+ while (!test_complete) {
+ int pgoff;
+ struct item *item;
+
+ pgoff = rand_r(&seeds[2]) % MAX_IDX;
+
+ item = xa_erase(&array, pgoff);
+ if (item)
+ item_free(item, pgoff);
+ }
+
+ rcu_unregister_thread();
+
+ return NULL;
+}
+
+static void *tag_entries_fn(void *arg)
+{
+ rcu_register_thread();
+
+ while (!test_complete) {
+ tag_tagged_items(&array, 0, MAX_IDX, 10, TAG, NEW_TAG);
+ }
+ rcu_unregister_thread();
+ return NULL;
+}
+
+/* This is a unit test for a bug found by the syzkaller tester */
+void iteration_test(unsigned order, unsigned test_duration)
+{
+ int i;
+
+ printv(1, "Running %siteration tests for %d seconds\n",
+ order > 0 ? "multiorder " : "", test_duration);
+
+ max_order = order;
+ test_complete = false;
+
+ for (i = 0; i < 3; i++)
+ seeds[i] = rand();
+
+ if (pthread_create(&threads[0], NULL, tagged_iteration_fn, NULL)) {
+ perror("create tagged iteration thread");
+ exit(1);
+ }
+ if (pthread_create(&threads[1], NULL, untagged_iteration_fn, NULL)) {
+ perror("create untagged iteration thread");
+ exit(1);
+ }
+ if (pthread_create(&threads[2], NULL, add_entries_fn, NULL)) {
+ perror("create add entry thread");
+ exit(1);
+ }
+ if (pthread_create(&threads[3], NULL, remove_entries_fn, NULL)) {
+ perror("create remove entry thread");
+ exit(1);
+ }
+ if (pthread_create(&threads[4], NULL, tag_entries_fn, NULL)) {
+ perror("create tag entry thread");
+ exit(1);
+ }
+
+ sleep(test_duration);
+ test_complete = true;
+
+ for (i = 0; i < NUM_THREADS; i++) {
+ if (pthread_join(threads[i], NULL)) {
+ perror("pthread_join");
+ exit(1);
+ }
+ }
+
+ item_kill_tree(&array);
+}