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1/*
2 * Module-based torture test facility for locking
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
17 *
18 * Copyright (C) IBM Corporation, 2014
19 *
20 * Author: Paul E. McKenney <paulmck@us.ibm.com>
21 * Based on kernel/rcu/torture.c.
22 */
23#include <linux/types.h>
24#include <linux/kernel.h>
25#include <linux/init.h>
26#include <linux/module.h>
27#include <linux/kthread.h>
28#include <linux/err.h>
29#include <linux/spinlock.h>
30#include <linux/smp.h>
31#include <linux/interrupt.h>
32#include <linux/sched.h>
33#include <linux/atomic.h>
34#include <linux/bitops.h>
35#include <linux/completion.h>
36#include <linux/moduleparam.h>
37#include <linux/percpu.h>
38#include <linux/notifier.h>
39#include <linux/reboot.h>
40#include <linux/freezer.h>
41#include <linux/cpu.h>
42#include <linux/delay.h>
43#include <linux/stat.h>
44#include <linux/slab.h>
45#include <linux/trace_clock.h>
46#include <asm/byteorder.h>
47#include <linux/torture.h>
48
49MODULE_LICENSE("GPL");
50MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
51
52torture_param(int, nwriters_stress, -1,
53 "Number of write-locking stress-test threads");
54torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
55torture_param(int, onoff_interval, 0,
56 "Time between CPU hotplugs (s), 0=disable");
57torture_param(int, shuffle_interval, 3,
58 "Number of jiffies between shuffles, 0=disable");
59torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
60torture_param(int, stat_interval, 60,
61 "Number of seconds between stats printk()s");
62torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
63torture_param(bool, verbose, true,
64 "Enable verbose debugging printk()s");
65
66static char *torture_type = "spin_lock";
67module_param(torture_type, charp, 0444);
68MODULE_PARM_DESC(torture_type,
69 "Type of lock to torture (spin_lock, spin_lock_irq, ...)");
70
71static atomic_t n_lock_torture_errors;
72
73static struct task_struct *stats_task;
74static struct task_struct **writer_tasks;
75
76static int nrealwriters_stress;
77static bool lock_is_write_held;
78
79struct lock_writer_stress_stats {
80 long n_write_lock_fail;
81 long n_write_lock_acquired;
82};
83static struct lock_writer_stress_stats *lwsa;
84
85#if defined(MODULE) || defined(CONFIG_LOCK_TORTURE_TEST_RUNNABLE)
86#define LOCKTORTURE_RUNNABLE_INIT 1
87#else
88#define LOCKTORTURE_RUNNABLE_INIT 0
89#endif
90int locktorture_runnable = LOCKTORTURE_RUNNABLE_INIT;
91module_param(locktorture_runnable, int, 0444);
92MODULE_PARM_DESC(locktorture_runnable, "Start locktorture at boot");
93
94/* Forward reference. */
95static void lock_torture_cleanup(void);
96
97/*
98 * Operations vector for selecting different types of tests.
99 */
100struct lock_torture_ops {
101 void (*init)(void);
102 int (*writelock)(void);
103 void (*write_delay)(struct torture_random_state *trsp);
104 void (*writeunlock)(void);
105 unsigned long flags;
106 const char *name;
107};
108
109static struct lock_torture_ops *cur_ops;
110
111/*
112 * Definitions for lock torture testing.
113 */
114
115static int torture_lock_busted_write_lock(void)
116{
117 return 0; /* BUGGY, do not use in real life!!! */
118}
119
120static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
121{
122 const unsigned long longdelay_us = 100;
123
124 /* We want a long delay occasionally to force massive contention. */
125 if (!(torture_random(trsp) %
126 (nrealwriters_stress * 2000 * longdelay_us)))
127 mdelay(longdelay_us);
128#ifdef CONFIG_PREEMPT
129 if (!(torture_random(trsp) % (nrealwriters_stress * 20000)))
130 preempt_schedule(); /* Allow test to be preempted. */
131#endif
132}
133
134static void torture_lock_busted_write_unlock(void)
135{
136 /* BUGGY, do not use in real life!!! */
137}
138
139static struct lock_torture_ops lock_busted_ops = {
140 .writelock = torture_lock_busted_write_lock,
141 .write_delay = torture_lock_busted_write_delay,
142 .writeunlock = torture_lock_busted_write_unlock,
143 .name = "lock_busted"
144};
145
146static DEFINE_SPINLOCK(torture_spinlock);
147
148static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock)
149{
150 spin_lock(&torture_spinlock);
151 return 0;
152}
153
154static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
155{
156 const unsigned long shortdelay_us = 2;
157 const unsigned long longdelay_us = 100;
158
159 /* We want a short delay mostly to emulate likely code, and
160 * we want a long delay occasionally to force massive contention.
161 */
162 if (!(torture_random(trsp) %
163 (nrealwriters_stress * 2000 * longdelay_us)))
164 mdelay(longdelay_us);
165 if (!(torture_random(trsp) %
166 (nrealwriters_stress * 2 * shortdelay_us)))
167 udelay(shortdelay_us);
168#ifdef CONFIG_PREEMPT
169 if (!(torture_random(trsp) % (nrealwriters_stress * 20000)))
170 preempt_schedule(); /* Allow test to be preempted. */
171#endif
172}
173
174static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock)
175{
176 spin_unlock(&torture_spinlock);
177}
178
179static struct lock_torture_ops spin_lock_ops = {
180 .writelock = torture_spin_lock_write_lock,
181 .write_delay = torture_spin_lock_write_delay,
182 .writeunlock = torture_spin_lock_write_unlock,
183 .name = "spin_lock"
184};
185
186static int torture_spin_lock_write_lock_irq(void)
187__acquires(torture_spinlock_irq)
188{
189 unsigned long flags;
190
191 spin_lock_irqsave(&torture_spinlock, flags);
192 cur_ops->flags = flags;
193 return 0;
194}
195
196static void torture_lock_spin_write_unlock_irq(void)
197__releases(torture_spinlock)
198{
199 spin_unlock_irqrestore(&torture_spinlock, cur_ops->flags);
200}
201
202static struct lock_torture_ops spin_lock_irq_ops = {
203 .writelock = torture_spin_lock_write_lock_irq,
204 .write_delay = torture_spin_lock_write_delay,
205 .writeunlock = torture_lock_spin_write_unlock_irq,
206 .name = "spin_lock_irq"
207};
208
209/*
210 * Lock torture writer kthread. Repeatedly acquires and releases
211 * the lock, checking for duplicate acquisitions.
212 */
213static int lock_torture_writer(void *arg)
214{
215 struct lock_writer_stress_stats *lwsp = arg;
216 static DEFINE_TORTURE_RANDOM(rand);
217
218 VERBOSE_TOROUT_STRING("lock_torture_writer task started");
219 set_user_nice(current, 19);
220
221 do {
222 schedule_timeout_uninterruptible(1);
223 cur_ops->writelock();
224 if (WARN_ON_ONCE(lock_is_write_held))
225 lwsp->n_write_lock_fail++;
226 lock_is_write_held = 1;
227 lwsp->n_write_lock_acquired++;
228 cur_ops->write_delay(&rand);
229 lock_is_write_held = 0;
230 cur_ops->writeunlock();
231 stutter_wait("lock_torture_writer");
232 } while (!torture_must_stop());
233 torture_kthread_stopping("lock_torture_writer");
234 return 0;
235}
236
237/*
238 * Create an lock-torture-statistics message in the specified buffer.
239 */
240static void lock_torture_printk(char *page)
241{
242 bool fail = 0;
243 int i;
244 long max = 0;
245 long min = lwsa[0].n_write_lock_acquired;
246 long long sum = 0;
247
248 for (i = 0; i < nrealwriters_stress; i++) {
249 if (lwsa[i].n_write_lock_fail)
250 fail = true;
251 sum += lwsa[i].n_write_lock_acquired;
252 if (max < lwsa[i].n_write_lock_fail)
253 max = lwsa[i].n_write_lock_fail;
254 if (min > lwsa[i].n_write_lock_fail)
255 min = lwsa[i].n_write_lock_fail;
256 }
257 page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG);
258 page += sprintf(page,
259 "Writes: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
260 sum, max, min, max / 2 > min ? "???" : "",
261 fail, fail ? "!!!" : "");
262 if (fail)
263 atomic_inc(&n_lock_torture_errors);
264}
265
266/*
267 * Print torture statistics. Caller must ensure that there is only one
268 * call to this function at a given time!!! This is normally accomplished
269 * by relying on the module system to only have one copy of the module
270 * loaded, and then by giving the lock_torture_stats kthread full control
271 * (or the init/cleanup functions when lock_torture_stats thread is not
272 * running).
273 */
274static void lock_torture_stats_print(void)
275{
276 int size = nrealwriters_stress * 200 + 8192;
277 char *buf;
278
279 buf = kmalloc(size, GFP_KERNEL);
280 if (!buf) {
281 pr_err("lock_torture_stats_print: Out of memory, need: %d",
282 size);
283 return;
284 }
285 lock_torture_printk(buf);
286 pr_alert("%s", buf);
287 kfree(buf);
288}
289
290/*
291 * Periodically prints torture statistics, if periodic statistics printing
292 * was specified via the stat_interval module parameter.
293 *
294 * No need to worry about fullstop here, since this one doesn't reference
295 * volatile state or register callbacks.
296 */
297static int lock_torture_stats(void *arg)
298{
299 VERBOSE_TOROUT_STRING("lock_torture_stats task started");
300 do {
301 schedule_timeout_interruptible(stat_interval * HZ);
302 lock_torture_stats_print();
303 torture_shutdown_absorb("lock_torture_stats");
304 } while (!torture_must_stop());
305 torture_kthread_stopping("lock_torture_stats");
306 return 0;
307}
308
309static inline void
310lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
311 const char *tag)
312{
313 pr_alert("%s" TORTURE_FLAG
314 "--- %s: nwriters_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
315 torture_type, tag, nrealwriters_stress, stat_interval, verbose,
316 shuffle_interval, stutter, shutdown_secs,
317 onoff_interval, onoff_holdoff);
318}
319
320static void lock_torture_cleanup(void)
321{
322 int i;
323
324 if (torture_cleanup())
325 return;
326
327 if (writer_tasks) {
328 for (i = 0; i < nrealwriters_stress; i++)
329 torture_stop_kthread(lock_torture_writer,
330 writer_tasks[i]);
331 kfree(writer_tasks);
332 writer_tasks = NULL;
333 }
334
335 torture_stop_kthread(lock_torture_stats, stats_task);
336 lock_torture_stats_print(); /* -After- the stats thread is stopped! */
337
338 if (atomic_read(&n_lock_torture_errors))
339 lock_torture_print_module_parms(cur_ops,
340 "End of test: FAILURE");
341 else if (torture_onoff_failures())
342 lock_torture_print_module_parms(cur_ops,
343 "End of test: LOCK_HOTPLUG");
344 else
345 lock_torture_print_module_parms(cur_ops,
346 "End of test: SUCCESS");
347}
348
349static int __init lock_torture_init(void)
350{
351 int i;
352 int firsterr = 0;
353 static struct lock_torture_ops *torture_ops[] = {
354 &lock_busted_ops, &spin_lock_ops, &spin_lock_irq_ops,
355 };
356
357 torture_init_begin(torture_type, verbose, &locktorture_runnable);
358
359 /* Process args and tell the world that the torturer is on the job. */
360 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
361 cur_ops = torture_ops[i];
362 if (strcmp(torture_type, cur_ops->name) == 0)
363 break;
364 }
365 if (i == ARRAY_SIZE(torture_ops)) {
366 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
367 torture_type);
368 pr_alert("lock-torture types:");
369 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
370 pr_alert(" %s", torture_ops[i]->name);
371 pr_alert("\n");
372 torture_init_end();
373 return -EINVAL;
374 }
375 if (cur_ops->init)
376 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
377
378 if (nwriters_stress >= 0)
379 nrealwriters_stress = nwriters_stress;
380 else
381 nrealwriters_stress = 2 * num_online_cpus();
382 lock_torture_print_module_parms(cur_ops, "Start of test");
383
384 /* Initialize the statistics so that each run gets its own numbers. */
385
386 lock_is_write_held = 0;
387 lwsa = kmalloc(sizeof(*lwsa) * nrealwriters_stress, GFP_KERNEL);
388 if (lwsa == NULL) {
389 VERBOSE_TOROUT_STRING("lwsa: Out of memory");
390 firsterr = -ENOMEM;
391 goto unwind;
392 }
393 for (i = 0; i < nrealwriters_stress; i++) {
394 lwsa[i].n_write_lock_fail = 0;
395 lwsa[i].n_write_lock_acquired = 0;
396 }
397
398 /* Start up the kthreads. */
399
400 if (onoff_interval > 0) {
401 firsterr = torture_onoff_init(onoff_holdoff * HZ,
402 onoff_interval * HZ);
403 if (firsterr)
404 goto unwind;
405 }
406 if (shuffle_interval > 0) {
407 firsterr = torture_shuffle_init(shuffle_interval);
408 if (firsterr)
409 goto unwind;
410 }
411 if (shutdown_secs > 0) {
412 firsterr = torture_shutdown_init(shutdown_secs,
413 lock_torture_cleanup);
414 if (firsterr)
415 goto unwind;
416 }
417 if (stutter > 0) {
418 firsterr = torture_stutter_init(stutter);
419 if (firsterr)
420 goto unwind;
421 }
422
423 writer_tasks = kzalloc(nrealwriters_stress * sizeof(writer_tasks[0]),
424 GFP_KERNEL);
425 if (writer_tasks == NULL) {
426 VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
427 firsterr = -ENOMEM;
428 goto unwind;
429 }
430 for (i = 0; i < nrealwriters_stress; i++) {
431 firsterr = torture_create_kthread(lock_torture_writer, &lwsa[i],
432 writer_tasks[i]);
433 if (firsterr)
434 goto unwind;
435 }
436 if (stat_interval > 0) {
437 firsterr = torture_create_kthread(lock_torture_stats, NULL,
438 stats_task);
439 if (firsterr)
440 goto unwind;
441 }
442 torture_init_end();
443 return 0;
444
445unwind:
446 torture_init_end();
447 lock_torture_cleanup();
448 return firsterr;
449}
450
451module_init(lock_torture_init);
452module_exit(lock_torture_cleanup);