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Diffstat (limited to 'tools/testing/radix-tree/iteration_check.c')
| -rw-r--r-- | tools/testing/radix-tree/iteration_check.c | 180 |
1 files changed, 180 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 000000000000..9adb8e7415a6 --- /dev/null +++ b/tools/testing/radix-tree/iteration_check.c @@ -0,0 +1,180 @@ +/* + * iteration_check.c: test races having to do with radix tree iteration + * Copyright (c) 2016 Intel Corporation + * Author: Ross Zwisler <ross.zwisler@linux.intel.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope 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. + */ +#include <linux/radix-tree.h> +#include <pthread.h> +#include "test.h" + +#define NUM_THREADS 4 +#define TAG 0 +static pthread_mutex_t tree_lock = PTHREAD_MUTEX_INITIALIZER; +static pthread_t threads[NUM_THREADS]; +RADIX_TREE(tree, GFP_KERNEL); +bool test_complete; + +/* relentlessly fill the tree with tagged entries */ +static void *add_entries_fn(void *arg) +{ + int pgoff; + + while (!test_complete) { + for (pgoff = 0; pgoff < 100; pgoff++) { + pthread_mutex_lock(&tree_lock); + if (item_insert(&tree, pgoff) == 0) + item_tag_set(&tree, pgoff, TAG); + pthread_mutex_unlock(&tree_lock); + } + } + + return NULL; +} + +/* + * Iterate over the tagged entries, doing a radix_tree_iter_retry() as we find + * things that have been removed and randomly resetting our iteration to the + * next chunk with radix_tree_iter_next(). Both radix_tree_iter_retry() and + * radix_tree_iter_next() cause radix_tree_next_slot() to be called with a + * NULL 'slot' variable. + */ +static void *tagged_iteration_fn(void *arg) +{ + struct radix_tree_iter iter; + void **slot; + + while (!test_complete) { + rcu_read_lock(); + radix_tree_for_each_tagged(slot, &tree, &iter, 0, TAG) { + void *entry; + int i; + + /* busy wait to let removals happen */ + for (i = 0; i < 1000000; i++) + ; + + entry = radix_tree_deref_slot(slot); + if (unlikely(!entry)) + continue; + + if (radix_tree_deref_retry(entry)) { + slot = radix_tree_iter_retry(&iter); + continue; + } + + if (rand() % 50 == 0) + slot = radix_tree_iter_next(&iter); + } + rcu_read_unlock(); + } + + return NULL; +} + +/* + * Iterate over the entries, doing a radix_tree_iter_retry() as we find things + * that have been removed and randomly resetting our iteration to the next + * chunk with radix_tree_iter_next(). Both radix_tree_iter_retry() and + * radix_tree_iter_next() cause radix_tree_next_slot() to be called with a + * NULL 'slot' variable. + */ +static void *untagged_iteration_fn(void *arg) +{ + struct radix_tree_iter iter; + void **slot; + + while (!test_complete) { + rcu_read_lock(); + radix_tree_for_each_slot(slot, &tree, &iter, 0) { + void *entry; + int i; + + /* busy wait to let removals happen */ + for (i = 0; i < 1000000; i++) + ; + + entry = radix_tree_deref_slot(slot); + if (unlikely(!entry)) + continue; + + if (radix_tree_deref_retry(entry)) { + slot = radix_tree_iter_retry(&iter); + continue; + } + + if (rand() % 50 == 0) + slot = radix_tree_iter_next(&iter); + } + rcu_read_unlock(); + } + + return NULL; +} + +/* + * Randomly remove entries to help induce radix_tree_iter_retry() calls in the + * two iteration functions. + */ +static void *remove_entries_fn(void *arg) +{ + while (!test_complete) { + int pgoff; + + pgoff = rand() % 100; + + pthread_mutex_lock(&tree_lock); + item_delete(&tree, pgoff); + pthread_mutex_unlock(&tree_lock); + } + + return NULL; +} + +/* This is a unit test for a bug found by the syzkaller tester */ +void iteration_test(void) +{ + int i; + + printf("Running iteration tests for 10 seconds\n"); + + srand(time(0)); + test_complete = false; + + if (pthread_create(&threads[0], NULL, tagged_iteration_fn, NULL)) { + perror("pthread_create"); + exit(1); + } + if (pthread_create(&threads[1], NULL, untagged_iteration_fn, NULL)) { + perror("pthread_create"); + exit(1); + } + if (pthread_create(&threads[2], NULL, add_entries_fn, NULL)) { + perror("pthread_create"); + exit(1); + } + if (pthread_create(&threads[3], NULL, remove_entries_fn, NULL)) { + perror("pthread_create"); + exit(1); + } + + sleep(10); + test_complete = true; + + for (i = 0; i < NUM_THREADS; i++) { + if (pthread_join(threads[i], NULL)) { + perror("pthread_join"); + exit(1); + } + } + + item_kill_tree(&tree); +} |