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/*
* iteration_check.c: test races having to do with xarray 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 <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);
}
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