aboutsummaryrefslogtreecommitdiff
path: root/lib/test_lockup.c
blob: 864554e769738a807d6cbe793b3796b8ec2a1e4b (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
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
// SPDX-License-Identifier: GPL-2.0
/*
 * Test module to generate lockups
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/sched/signal.h>
#include <linux/sched/clock.h>
#include <linux/cpu.h>
#include <linux/nmi.h>
#include <linux/mm.h>
#include <linux/uaccess.h>
#include <linux/file.h>

static unsigned int time_secs;
module_param(time_secs, uint, 0600);
MODULE_PARM_DESC(time_secs, "lockup time in seconds, default 0");

static unsigned int time_nsecs;
module_param(time_nsecs, uint, 0600);
MODULE_PARM_DESC(time_nsecs, "nanoseconds part of lockup time, default 0");

static unsigned int cooldown_secs;
module_param(cooldown_secs, uint, 0600);
MODULE_PARM_DESC(cooldown_secs, "cooldown time between iterations in seconds, default 0");

static unsigned int cooldown_nsecs;
module_param(cooldown_nsecs, uint, 0600);
MODULE_PARM_DESC(cooldown_nsecs, "nanoseconds part of cooldown, default 0");

static unsigned int iterations = 1;
module_param(iterations, uint, 0600);
MODULE_PARM_DESC(iterations, "lockup iterations, default 1");

static bool all_cpus;
module_param(all_cpus, bool, 0400);
MODULE_PARM_DESC(all_cpus, "trigger lockup at all cpus at once");

static int wait_state;
static char *state = "R";
module_param(state, charp, 0400);
MODULE_PARM_DESC(state, "wait in 'R' running (default), 'D' uninterruptible, 'K' killable, 'S' interruptible state");

static bool use_hrtimer;
module_param(use_hrtimer, bool, 0400);
MODULE_PARM_DESC(use_hrtimer, "use high-resolution timer for sleeping");

static bool iowait;
module_param(iowait, bool, 0400);
MODULE_PARM_DESC(iowait, "account sleep time as iowait");

static bool lock_read;
module_param(lock_read, bool, 0400);
MODULE_PARM_DESC(lock_read, "lock read-write locks for read");

static bool lock_single;
module_param(lock_single, bool, 0400);
MODULE_PARM_DESC(lock_single, "acquire locks only at one cpu");

static bool reacquire_locks;
module_param(reacquire_locks, bool, 0400);
MODULE_PARM_DESC(reacquire_locks, "release and reacquire locks/irq/preempt between iterations");

static bool touch_softlockup;
module_param(touch_softlockup, bool, 0600);
MODULE_PARM_DESC(touch_softlockup, "touch soft-lockup watchdog between iterations");

static bool touch_hardlockup;
module_param(touch_hardlockup, bool, 0600);
MODULE_PARM_DESC(touch_hardlockup, "touch hard-lockup watchdog between iterations");

static bool call_cond_resched;
module_param(call_cond_resched, bool, 0600);
MODULE_PARM_DESC(call_cond_resched, "call cond_resched() between iterations");

static bool measure_lock_wait;
module_param(measure_lock_wait, bool, 0400);
MODULE_PARM_DESC(measure_lock_wait, "measure lock wait time");

static unsigned long lock_wait_threshold = ULONG_MAX;
module_param(lock_wait_threshold, ulong, 0400);
MODULE_PARM_DESC(lock_wait_threshold, "print lock wait time longer than this in nanoseconds, default off");

static bool test_disable_irq;
module_param_named(disable_irq, test_disable_irq, bool, 0400);
MODULE_PARM_DESC(disable_irq, "disable interrupts: generate hard-lockups");

static bool disable_softirq;
module_param(disable_softirq, bool, 0400);
MODULE_PARM_DESC(disable_softirq, "disable bottom-half irq handlers");

static bool disable_preempt;
module_param(disable_preempt, bool, 0400);
MODULE_PARM_DESC(disable_preempt, "disable preemption: generate soft-lockups");

static bool lock_rcu;
module_param(lock_rcu, bool, 0400);
MODULE_PARM_DESC(lock_rcu, "grab rcu_read_lock: generate rcu stalls");

static bool lock_mmap_sem;
module_param(lock_mmap_sem, bool, 0400);
MODULE_PARM_DESC(lock_mmap_sem, "lock mm->mmap_lock: block procfs interfaces");

static unsigned long lock_rwsem_ptr;
module_param_unsafe(lock_rwsem_ptr, ulong, 0400);
MODULE_PARM_DESC(lock_rwsem_ptr, "lock rw_semaphore at address");

static unsigned long lock_mutex_ptr;
module_param_unsafe(lock_mutex_ptr, ulong, 0400);
MODULE_PARM_DESC(lock_mutex_ptr, "lock mutex at address");

static unsigned long lock_spinlock_ptr;
module_param_unsafe(lock_spinlock_ptr, ulong, 0400);
MODULE_PARM_DESC(lock_spinlock_ptr, "lock spinlock at address");

static unsigned long lock_rwlock_ptr;
module_param_unsafe(lock_rwlock_ptr, ulong, 0400);
MODULE_PARM_DESC(lock_rwlock_ptr, "lock rwlock at address");

static unsigned int alloc_pages_nr;
module_param_unsafe(alloc_pages_nr, uint, 0600);
MODULE_PARM_DESC(alloc_pages_nr, "allocate and free pages under locks");

static unsigned int alloc_pages_order;
module_param(alloc_pages_order, uint, 0400);
MODULE_PARM_DESC(alloc_pages_order, "page order to allocate");

static gfp_t alloc_pages_gfp = GFP_KERNEL;
module_param_unsafe(alloc_pages_gfp, uint, 0400);
MODULE_PARM_DESC(alloc_pages_gfp, "allocate pages with this gfp_mask, default GFP_KERNEL");

static bool alloc_pages_atomic;
module_param(alloc_pages_atomic, bool, 0400);
MODULE_PARM_DESC(alloc_pages_atomic, "allocate pages with GFP_ATOMIC");

static bool reallocate_pages;
module_param(reallocate_pages, bool, 0400);
MODULE_PARM_DESC(reallocate_pages, "free and allocate pages between iterations");

struct file *test_file;
static struct inode *test_inode;
static char test_file_path[256];
module_param_string(file_path, test_file_path, sizeof(test_file_path), 0400);
MODULE_PARM_DESC(file_path, "file path to test");

static bool test_lock_inode;
module_param_named(lock_inode, test_lock_inode, bool, 0400);
MODULE_PARM_DESC(lock_inode, "lock file -> inode -> i_rwsem");

static bool test_lock_mapping;
module_param_named(lock_mapping, test_lock_mapping, bool, 0400);
MODULE_PARM_DESC(lock_mapping, "lock file -> mapping -> i_mmap_rwsem");

static bool test_lock_sb_umount;
module_param_named(lock_sb_umount, test_lock_sb_umount, bool, 0400);
MODULE_PARM_DESC(lock_sb_umount, "lock file -> sb -> s_umount");

static atomic_t alloc_pages_failed = ATOMIC_INIT(0);

static atomic64_t max_lock_wait = ATOMIC64_INIT(0);

static struct task_struct *main_task;
static int master_cpu;

static void test_lock(bool master, bool verbose)
{
	u64 wait_start;

	if (measure_lock_wait)
		wait_start = local_clock();

	if (lock_mutex_ptr && master) {
		if (verbose)
			pr_notice("lock mutex %ps\n", (void *)lock_mutex_ptr);
		mutex_lock((struct mutex *)lock_mutex_ptr);
	}

	if (lock_rwsem_ptr && master) {
		if (verbose)
			pr_notice("lock rw_semaphore %ps\n",
				  (void *)lock_rwsem_ptr);
		if (lock_read)
			down_read((struct rw_semaphore *)lock_rwsem_ptr);
		else
			down_write((struct rw_semaphore *)lock_rwsem_ptr);
	}

	if (lock_mmap_sem && master) {
		if (verbose)
			pr_notice("lock mmap_lock pid=%d\n", main_task->pid);
		if (lock_read)
			mmap_read_lock(main_task->mm);
		else
			mmap_write_lock(main_task->mm);
	}

	if (test_disable_irq)
		local_irq_disable();

	if (disable_softirq)
		local_bh_disable();

	if (disable_preempt)
		preempt_disable();

	if (lock_rcu)
		rcu_read_lock();

	if (lock_spinlock_ptr && master) {
		if (verbose)
			pr_notice("lock spinlock %ps\n",
				  (void *)lock_spinlock_ptr);
		spin_lock((spinlock_t *)lock_spinlock_ptr);
	}

	if (lock_rwlock_ptr && master) {
		if (verbose)
			pr_notice("lock rwlock %ps\n",
				  (void *)lock_rwlock_ptr);
		if (lock_read)
			read_lock((rwlock_t *)lock_rwlock_ptr);
		else
			write_lock((rwlock_t *)lock_rwlock_ptr);
	}

	if (measure_lock_wait) {
		s64 cur_wait = local_clock() - wait_start;
		s64 max_wait = atomic64_read(&max_lock_wait);

		do {
			if (cur_wait < max_wait)
				break;
			max_wait = atomic64_cmpxchg(&max_lock_wait,
						    max_wait, cur_wait);
		} while (max_wait != cur_wait);

		if (cur_wait > lock_wait_threshold)
			pr_notice_ratelimited("lock wait %lld ns\n", cur_wait);
	}
}

static void test_unlock(bool master, bool verbose)
{
	if (lock_rwlock_ptr && master) {
		if (lock_read)
			read_unlock((rwlock_t *)lock_rwlock_ptr);
		else
			write_unlock((rwlock_t *)lock_rwlock_ptr);
		if (verbose)
			pr_notice("unlock rwlock %ps\n",
				  (void *)lock_rwlock_ptr);
	}

	if (lock_spinlock_ptr && master) {
		spin_unlock((spinlock_t *)lock_spinlock_ptr);
		if (verbose)
			pr_notice("unlock spinlock %ps\n",
				  (void *)lock_spinlock_ptr);
	}

	if (lock_rcu)
		rcu_read_unlock();

	if (disable_preempt)
		preempt_enable();

	if (disable_softirq)
		local_bh_enable();

	if (test_disable_irq)
		local_irq_enable();

	if (lock_mmap_sem && master) {
		if (lock_read)
			mmap_read_unlock(main_task->mm);
		else
			mmap_write_unlock(main_task->mm);
		if (verbose)
			pr_notice("unlock mmap_lock pid=%d\n", main_task->pid);
	}

	if (lock_rwsem_ptr && master) {
		if (lock_read)
			up_read((struct rw_semaphore *)lock_rwsem_ptr);
		else
			up_write((struct rw_semaphore *)lock_rwsem_ptr);
		if (verbose)
			pr_notice("unlock rw_semaphore %ps\n",
				  (void *)lock_rwsem_ptr);
	}

	if (lock_mutex_ptr && master) {
		mutex_unlock((struct mutex *)lock_mutex_ptr);
		if (verbose)
			pr_notice("unlock mutex %ps\n",
				  (void *)lock_mutex_ptr);
	}
}

static void test_alloc_pages(struct list_head *pages)
{
	struct page *page;
	unsigned int i;

	for (i = 0; i < alloc_pages_nr; i++) {
		page = alloc_pages(alloc_pages_gfp, alloc_pages_order);
		if (!page) {
			atomic_inc(&alloc_pages_failed);
			break;
		}
		list_add(&page->lru, pages);
	}
}

static void test_free_pages(struct list_head *pages)
{
	struct page *page, *next;

	list_for_each_entry_safe(page, next, pages, lru)
		__free_pages(page, alloc_pages_order);
	INIT_LIST_HEAD(pages);
}

static void test_wait(unsigned int secs, unsigned int nsecs)
{
	if (wait_state == TASK_RUNNING) {
		if (secs)
			mdelay(secs * MSEC_PER_SEC);
		if (nsecs)
			ndelay(nsecs);
		return;
	}

	__set_current_state(wait_state);
	if (use_hrtimer) {
		ktime_t time;

		time = ns_to_ktime((u64)secs * NSEC_PER_SEC + nsecs);
		schedule_hrtimeout(&time, HRTIMER_MODE_REL);
	} else {
		schedule_timeout(secs * HZ + nsecs_to_jiffies(nsecs));
	}
}

static void test_lockup(bool master)
{
	u64 lockup_start = local_clock();
	unsigned int iter = 0;
	LIST_HEAD(pages);

	pr_notice("Start on CPU%d\n", raw_smp_processor_id());

	test_lock(master, true);

	test_alloc_pages(&pages);

	while (iter++ < iterations && !signal_pending(main_task)) {

		if (iowait)
			current->in_iowait = 1;

		test_wait(time_secs, time_nsecs);

		if (iowait)
			current->in_iowait = 0;

		if (reallocate_pages)
			test_free_pages(&pages);

		if (reacquire_locks)
			test_unlock(master, false);

		if (touch_softlockup)
			touch_softlockup_watchdog();

		if (touch_hardlockup)
			touch_nmi_watchdog();

		if (call_cond_resched)
			cond_resched();

		test_wait(cooldown_secs, cooldown_nsecs);

		if (reacquire_locks)
			test_lock(master, false);

		if (reallocate_pages)
			test_alloc_pages(&pages);
	}

	pr_notice("Finish on CPU%d in %lld ns\n", raw_smp_processor_id(),
		  local_clock() - lockup_start);

	test_free_pages(&pages);

	test_unlock(master, true);
}

static DEFINE_PER_CPU(struct work_struct, test_works);

static void test_work_fn(struct work_struct *work)
{
	test_lockup(!lock_single ||
		    work == per_cpu_ptr(&test_works, master_cpu));
}

static bool test_kernel_ptr(unsigned long addr, int size)
{
	void *ptr = (void *)addr;
	char buf;

	if (!addr)
		return false;

	/* should be at least readable kernel address */
	if (access_ok(ptr, 1) ||
	    access_ok(ptr + size - 1, 1) ||
	    get_kernel_nofault(buf, ptr) ||
	    get_kernel_nofault(buf, ptr + size - 1)) {
		pr_err("invalid kernel ptr: %#lx\n", addr);
		return true;
	}

	return false;
}

static bool __maybe_unused test_magic(unsigned long addr, int offset,
				      unsigned int expected)
{
	void *ptr = (void *)addr + offset;
	unsigned int magic = 0;

	if (!addr)
		return false;

	if (get_kernel_nofault(magic, ptr) || magic != expected) {
		pr_err("invalid magic at %#lx + %#x = %#x, expected %#x\n",
		       addr, offset, magic, expected);
		return true;
	}

	return false;
}

static int __init test_lockup_init(void)
{
	u64 test_start = local_clock();

	main_task = current;

	switch (state[0]) {
	case 'S':
		wait_state = TASK_INTERRUPTIBLE;
		break;
	case 'D':
		wait_state = TASK_UNINTERRUPTIBLE;
		break;
	case 'K':
		wait_state = TASK_KILLABLE;
		break;
	case 'R':
		wait_state = TASK_RUNNING;
		break;
	default:
		pr_err("unknown state=%s\n", state);
		return -EINVAL;
	}

	if (alloc_pages_atomic)
		alloc_pages_gfp = GFP_ATOMIC;

	if (test_kernel_ptr(lock_spinlock_ptr, sizeof(spinlock_t)) ||
	    test_kernel_ptr(lock_rwlock_ptr, sizeof(rwlock_t)) ||
	    test_kernel_ptr(lock_mutex_ptr, sizeof(struct mutex)) ||
	    test_kernel_ptr(lock_rwsem_ptr, sizeof(struct rw_semaphore)))
		return -EINVAL;

#ifdef CONFIG_DEBUG_SPINLOCK
#ifdef CONFIG_PREEMPT_RT
	if (test_magic(lock_spinlock_ptr,
		       offsetof(spinlock_t, lock.wait_lock.magic),
		       SPINLOCK_MAGIC) ||
	    test_magic(lock_rwlock_ptr,
		       offsetof(rwlock_t, rtmutex.wait_lock.magic),
		       SPINLOCK_MAGIC) ||
	    test_magic(lock_mutex_ptr,
		       offsetof(struct mutex, lock.wait_lock.magic),
		       SPINLOCK_MAGIC) ||
	    test_magic(lock_rwsem_ptr,
		       offsetof(struct rw_semaphore, rtmutex.wait_lock.magic),
		       SPINLOCK_MAGIC))
		return -EINVAL;
#else
	if (test_magic(lock_spinlock_ptr,
		       offsetof(spinlock_t, rlock.magic),
		       SPINLOCK_MAGIC) ||
	    test_magic(lock_rwlock_ptr,
		       offsetof(rwlock_t, magic),
		       RWLOCK_MAGIC) ||
	    test_magic(lock_mutex_ptr,
		       offsetof(struct mutex, wait_lock.rlock.magic),
		       SPINLOCK_MAGIC) ||
	    test_magic(lock_rwsem_ptr,
		       offsetof(struct rw_semaphore, wait_lock.magic),
		       SPINLOCK_MAGIC))
		return -EINVAL;
#endif
#endif

	if ((wait_state != TASK_RUNNING ||
	     (call_cond_resched && !reacquire_locks) ||
	     (alloc_pages_nr && gfpflags_allow_blocking(alloc_pages_gfp))) &&
	    (test_disable_irq || disable_softirq || disable_preempt ||
	     lock_rcu || lock_spinlock_ptr || lock_rwlock_ptr)) {
		pr_err("refuse to sleep in atomic context\n");
		return -EINVAL;
	}

	if (lock_mmap_sem && !main_task->mm) {
		pr_err("no mm to lock mmap_lock\n");
		return -EINVAL;
	}

	if (test_file_path[0]) {
		test_file = filp_open(test_file_path, O_RDONLY, 0);
		if (IS_ERR(test_file)) {
			pr_err("failed to open %s: %ld\n", test_file_path, PTR_ERR(test_file));
			return PTR_ERR(test_file);
		}
		test_inode = file_inode(test_file);
	} else if (test_lock_inode ||
		   test_lock_mapping ||
		   test_lock_sb_umount) {
		pr_err("no file to lock\n");
		return -EINVAL;
	}

	if (test_lock_inode && test_inode)
		lock_rwsem_ptr = (unsigned long)&test_inode->i_rwsem;

	if (test_lock_mapping && test_file && test_file->f_mapping)
		lock_rwsem_ptr = (unsigned long)&test_file->f_mapping->i_mmap_rwsem;

	if (test_lock_sb_umount && test_inode)
		lock_rwsem_ptr = (unsigned long)&test_inode->i_sb->s_umount;

	pr_notice("START pid=%d time=%u +%u ns cooldown=%u +%u ns iterations=%u state=%s %s%s%s%s%s%s%s%s%s%s%s\n",
		  main_task->pid, time_secs, time_nsecs,
		  cooldown_secs, cooldown_nsecs, iterations, state,
		  all_cpus ? "all_cpus " : "",
		  iowait ? "iowait " : "",
		  test_disable_irq ? "disable_irq " : "",
		  disable_softirq ? "disable_softirq " : "",
		  disable_preempt ? "disable_preempt " : "",
		  lock_rcu ? "lock_rcu " : "",
		  lock_read ? "lock_read " : "",
		  touch_softlockup ? "touch_softlockup " : "",
		  touch_hardlockup ? "touch_hardlockup " : "",
		  call_cond_resched ? "call_cond_resched " : "",
		  reacquire_locks ? "reacquire_locks " : "");

	if (alloc_pages_nr)
		pr_notice("ALLOCATE PAGES nr=%u order=%u gfp=%pGg %s\n",
			  alloc_pages_nr, alloc_pages_order, &alloc_pages_gfp,
			  reallocate_pages ? "reallocate_pages " : "");

	if (all_cpus) {
		unsigned int cpu;

		cpus_read_lock();

		preempt_disable();
		master_cpu = smp_processor_id();
		for_each_online_cpu(cpu) {
			INIT_WORK(per_cpu_ptr(&test_works, cpu), test_work_fn);
			queue_work_on(cpu, system_highpri_wq,
				      per_cpu_ptr(&test_works, cpu));
		}
		preempt_enable();

		for_each_online_cpu(cpu)
			flush_work(per_cpu_ptr(&test_works, cpu));

		cpus_read_unlock();
	} else {
		test_lockup(true);
	}

	if (measure_lock_wait)
		pr_notice("Maximum lock wait: %lld ns\n",
			  atomic64_read(&max_lock_wait));

	if (alloc_pages_nr)
		pr_notice("Page allocation failed %u times\n",
			  atomic_read(&alloc_pages_failed));

	pr_notice("FINISH in %llu ns\n", local_clock() - test_start);

	if (test_file)
		fput(test_file);

	if (signal_pending(main_task))
		return -EINTR;

	return -EAGAIN;
}
module_init(test_lockup_init);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Konstantin Khlebnikov <khlebnikov@yandex-team.ru>");
MODULE_DESCRIPTION("Test module to generate lockups");