summaryrefslogtreecommitdiffstats
path: root/kernel/locking/locktorture.c
blob: 0955b885d0dc8eb5fe54aeeebe08c0eee6bd9cb7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
/*
 * Module-based torture test facility for locking
 *
 * 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.
 *
 * Copyright (C) IBM Corporation, 2014
 *
 * Author: Paul E. McKenney <paulmck@us.ibm.com>
 *	Based on kernel/rcu/torture.c.
 */
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/err.h>
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/completion.h>
#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/freezer.h>
#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/trace_clock.h>
#include <asm/byteorder.h>
#include <linux/torture.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");

torture_param(int, nwriters_stress, -1,
	     "Number of write-locking stress-test threads");
torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
torture_param(int, onoff_interval, 0,
	     "Time between CPU hotplugs (s), 0=disable");
torture_param(int, shuffle_interval, 3,
	     "Number of jiffies between shuffles, 0=disable");
torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
torture_param(int, stat_interval, 60,
	     "Number of seconds between stats printk()s");
torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
torture_param(bool, verbose, true,
	     "Enable verbose debugging printk()s");

static char *torture_type = "spin_lock";
module_param(torture_type, charp, 0444);
MODULE_PARM_DESC(torture_type,
		 "Type of lock to torture (spin_lock, spin_lock_irq, ...)");

static atomic_t n_lock_torture_errors;

static struct task_struct *stats_task;
static struct task_struct **writer_tasks;

static int nrealwriters_stress;
static bool lock_is_write_held;

struct lock_writer_stress_stats {
	long n_write_lock_fail;
	long n_write_lock_acquired;
};
static struct lock_writer_stress_stats *lwsa;

#if defined(MODULE)
#define LOCKTORTURE_RUNNABLE_INIT 1
#else
#define LOCKTORTURE_RUNNABLE_INIT 0
#endif
int locktorture_runnable = LOCKTORTURE_RUNNABLE_INIT;
module_param(locktorture_runnable, int, 0444);
MODULE_PARM_DESC(locktorture_runnable, "Start locktorture at module init");

/* Forward reference. */
static void lock_torture_cleanup(void);

/*
 * Operations vector for selecting different types of tests.
 */
struct lock_torture_ops {
	void (*init)(void);
	int (*writelock)(void);
	void (*write_delay)(struct torture_random_state *trsp);
	void (*writeunlock)(void);
	unsigned long flags;
	const char *name;
};

static struct lock_torture_ops *cur_ops;

/*
 * Definitions for lock torture testing.
 */

static int torture_lock_busted_write_lock(void)
{
	return 0;  /* BUGGY, do not use in real life!!! */
}

static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
{
	const unsigned long longdelay_us = 100;

	/* We want a long delay occasionally to force massive contention.  */
	if (!(torture_random(trsp) %
	      (nrealwriters_stress * 2000 * longdelay_us)))
		mdelay(longdelay_us);
#ifdef CONFIG_PREEMPT
	if (!(torture_random(trsp) % (nrealwriters_stress * 20000)))
		preempt_schedule();  /* Allow test to be preempted. */
#endif
}

static void torture_lock_busted_write_unlock(void)
{
	  /* BUGGY, do not use in real life!!! */
}

static struct lock_torture_ops lock_busted_ops = {
	.writelock	= torture_lock_busted_write_lock,
	.write_delay	= torture_lock_busted_write_delay,
	.writeunlock	= torture_lock_busted_write_unlock,
	.name		= "lock_busted"
};

static DEFINE_SPINLOCK(torture_spinlock);

static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock)
{
	spin_lock(&torture_spinlock);
	return 0;
}

static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
{
	const unsigned long shortdelay_us = 2;
	const unsigned long longdelay_us = 100;

	/* We want a short delay mostly to emulate likely code, and
	 * we want a long delay occasionally to force massive contention.
	 */
	if (!(torture_random(trsp) %
	      (nrealwriters_stress * 2000 * longdelay_us)))
		mdelay(longdelay_us);
	if (!(torture_random(trsp) %
	      (nrealwriters_stress * 2 * shortdelay_us)))
		udelay(shortdelay_us);
#ifdef CONFIG_PREEMPT
	if (!(torture_random(trsp) % (nrealwriters_stress * 20000)))
		preempt_schedule();  /* Allow test to be preempted. */
#endif
}

static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock)
{
	spin_unlock(&torture_spinlock);
}

static struct lock_torture_ops spin_lock_ops = {
	.writelock	= torture_spin_lock_write_lock,
	.write_delay	= torture_spin_lock_write_delay,
	.writeunlock	= torture_spin_lock_write_unlock,
	.name		= "spin_lock"
};

static int torture_spin_lock_write_lock_irq(void)
__acquires(torture_spinlock_irq)
{
	unsigned long flags;

	spin_lock_irqsave(&torture_spinlock, flags);
	cur_ops->flags = flags;
	return 0;
}

static void torture_lock_spin_write_unlock_irq(void)
__releases(torture_spinlock)
{
	spin_unlock_irqrestore(&torture_spinlock, cur_ops->flags);
}

static struct lock_torture_ops spin_lock_irq_ops = {
	.writelock	= torture_spin_lock_write_lock_irq,
	.write_delay	= torture_spin_lock_write_delay,
	.writeunlock	= torture_lock_spin_write_unlock_irq,
	.name		= "spin_lock_irq"
};

/*
 * Lock torture writer kthread.  Repeatedly acquires and releases
 * the lock, checking for duplicate acquisitions.
 */
static int lock_torture_writer(void *arg)
{
	struct lock_writer_stress_stats *lwsp = arg;
	static DEFINE_TORTURE_RANDOM(rand);

	VERBOSE_TOROUT_STRING("lock_torture_writer task started");
	set_user_nice(current, MAX_NICE);

	do {
		if ((torture_random(&rand) & 0xfffff) == 0)
			schedule_timeout_uninterruptible(1);
		cur_ops->writelock();
		if (WARN_ON_ONCE(lock_is_write_held))
			lwsp->n_write_lock_fail++;
		lock_is_write_held = 1;
		lwsp->n_write_lock_acquired++;
		cur_ops->write_delay(&rand);
		lock_is_write_held = 0;
		cur_ops->writeunlock();
		stutter_wait("lock_torture_writer");
	} while (!torture_must_stop());
	torture_kthread_stopping("lock_torture_writer");
	return 0;
}

/*
 * Create an lock-torture-statistics message in the specified buffer.
 */
static void lock_torture_printk(char *page)
{
	bool fail = 0;
	int i;
	long max = 0;
	long min = lwsa[0].n_write_lock_acquired;
	long long sum = 0;

	for (i = 0; i < nrealwriters_stress; i++) {
		if (lwsa[i].n_write_lock_fail)
			fail = true;
		sum += lwsa[i].n_write_lock_acquired;
		if (max < lwsa[i].n_write_lock_fail)
			max = lwsa[i].n_write_lock_fail;
		if (min > lwsa[i].n_write_lock_fail)
			min = lwsa[i].n_write_lock_fail;
	}
	page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG);
	page += sprintf(page,
			"Writes:  Total: %lld  Max/Min: %ld/%ld %s  Fail: %d %s\n",
			sum, max, min, max / 2 > min ? "???" : "",
			fail, fail ? "!!!" : "");
	if (fail)
		atomic_inc(&n_lock_torture_errors);
}

/*
 * Print torture statistics.  Caller must ensure that there is only one
 * call to this function at a given time!!!  This is normally accomplished
 * by relying on the module system to only have one copy of the module
 * loaded, and then by giving the lock_torture_stats kthread full control
 * (or the init/cleanup functions when lock_torture_stats thread is not
 * running).
 */
static void lock_torture_stats_print(void)
{
	int size = nrealwriters_stress * 200 + 8192;
	char *buf;

	buf = kmalloc(size, GFP_KERNEL);
	if (!buf) {
		pr_err("lock_torture_stats_print: Out of memory, need: %d",
		       size);
		return;
	}
	lock_torture_printk(buf);
	pr_alert("%s", buf);
	kfree(buf);
}

/*
 * Periodically prints torture statistics, if periodic statistics printing
 * was specified via the stat_interval module parameter.
 *
 * No need to worry about fullstop here, since this one doesn't reference
 * volatile state or register callbacks.
 */
static int lock_torture_stats(void *arg)
{
	VERBOSE_TOROUT_STRING("lock_torture_stats task started");
	do {
		schedule_timeout_interruptible(stat_interval * HZ);
		lock_torture_stats_print();
		torture_shutdown_absorb("lock_torture_stats");
	} while (!torture_must_stop());
	torture_kthread_stopping("lock_torture_stats");
	return 0;
}

static inline void
lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
				const char *tag)
{
	pr_alert("%s" TORTURE_FLAG
		 "--- %s: nwriters_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
		 torture_type, tag, nrealwriters_stress, stat_interval, verbose,
		 shuffle_interval, stutter, shutdown_secs,
		 onoff_interval, onoff_holdoff);
}

static void lock_torture_cleanup(void)
{
	int i;

	if (torture_cleanup())
		return;

	if (writer_tasks) {
		for (i = 0; i < nrealwriters_stress; i++)
			torture_stop_kthread(lock_torture_writer,
					     writer_tasks[i]);
		kfree(writer_tasks);
		writer_tasks = NULL;
	}

	torture_stop_kthread(lock_torture_stats, stats_task);
	lock_torture_stats_print();  /* -After- the stats thread is stopped! */

	if (atomic_read(&n_lock_torture_errors))
		lock_torture_print_module_parms(cur_ops,
						"End of test: FAILURE");
	else if (torture_onoff_failures())
		lock_torture_print_module_parms(cur_ops,
						"End of test: LOCK_HOTPLUG");
	else
		lock_torture_print_module_parms(cur_ops,
						"End of test: SUCCESS");
}

static int __init lock_torture_init(void)
{
	int i;
	int firsterr = 0;
	static struct lock_torture_ops *torture_ops[] = {
		&lock_busted_ops, &spin_lock_ops, &spin_lock_irq_ops,
	};

	if (!torture_init_begin(torture_type, verbose, &locktorture_runnable))
		return -EBUSY;

	/* Process args and tell the world that the torturer is on the job. */
	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
		cur_ops = torture_ops[i];
		if (strcmp(torture_type, cur_ops->name) == 0)
			break;
	}
	if (i == ARRAY_SIZE(torture_ops)) {
		pr_alert("lock-torture: invalid torture type: \"%s\"\n",
			 torture_type);
		pr_alert("lock-torture types:");
		for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
			pr_alert(" %s", torture_ops[i]->name);
		pr_alert("\n");
		torture_init_end();
		return -EINVAL;
	}
	if (cur_ops->init)
		cur_ops->init(); /* no "goto unwind" prior to this point!!! */

	if (nwriters_stress >= 0)
		nrealwriters_stress = nwriters_stress;
	else
		nrealwriters_stress = 2 * num_online_cpus();
	lock_torture_print_module_parms(cur_ops, "Start of test");

	/* Initialize the statistics so that each run gets its own numbers. */

	lock_is_write_held = 0;
	lwsa = kmalloc(sizeof(*lwsa) * nrealwriters_stress, GFP_KERNEL);
	if (lwsa == NULL) {
		VERBOSE_TOROUT_STRING("lwsa: Out of memory");
		firsterr = -ENOMEM;
		goto unwind;
	}
	for (i = 0; i < nrealwriters_stress; i++) {
		lwsa[i].n_write_lock_fail = 0;
		lwsa[i].n_write_lock_acquired = 0;
	}

	/* Start up the kthreads. */

	if (onoff_interval > 0) {
		firsterr = torture_onoff_init(onoff_holdoff * HZ,
					      onoff_interval * HZ);
		if (firsterr)
			goto unwind;
	}
	if (shuffle_interval > 0) {
		firsterr = torture_shuffle_init(shuffle_interval);
		if (firsterr)
			goto unwind;
	}
	if (shutdown_secs > 0) {
		firsterr = torture_shutdown_init(shutdown_secs,
						 lock_torture_cleanup);
		if (firsterr)
			goto unwind;
	}
	if (stutter > 0) {
		firsterr = torture_stutter_init(stutter);
		if (firsterr)
			goto unwind;
	}

	writer_tasks = kzalloc(nrealwriters_stress * sizeof(writer_tasks[0]),
			       GFP_KERNEL);
	if (writer_tasks == NULL) {
		VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
		firsterr = -ENOMEM;
		goto unwind;
	}
	for (i = 0; i < nrealwriters_stress; i++) {
		firsterr = torture_create_kthread(lock_torture_writer, &lwsa[i],
						  writer_tasks[i]);
		if (firsterr)
			goto unwind;
	}
	if (stat_interval > 0) {
		firsterr = torture_create_kthread(lock_torture_stats, NULL,
						  stats_task);
		if (firsterr)
			goto unwind;
	}
	torture_init_end();
	return 0;

unwind:
	torture_init_end();
	lock_torture_cleanup();
	return firsterr;
}

module_init(lock_torture_init);
module_exit(lock_torture_cleanup);