kernel/locking/locktorture.c

   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/mutex.h>
  31 #include <linux/smp.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/sched.h>
  34 #include <linux/atomic.h>
  35 #include <linux/bitops.h>
  36 #include <linux/completion.h>
  37 #include <linux/moduleparam.h>
  38 #include <linux/percpu.h>
  39 #include <linux/notifier.h>
  40 #include <linux/reboot.h>
  41 #include <linux/freezer.h>
  42 #include <linux/cpu.h>
  43 #include <linux/delay.h>
  44 #include <linux/stat.h>
  45 #include <linux/slab.h>
  46 #include <linux/trace_clock.h>
  47 #include <asm/byteorder.h>
  48 #include <linux/torture.h>
  49
  50 MODULE_LICENSE("GPL");
  51 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
  52
  53 torture_param(int, nwriters_stress, -1,
  54              "Number of write-locking stress-test threads");
  55 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
  56 torture_param(int, onoff_interval, 0,
  57              "Time between CPU hotplugs (s), 0=disable");
  58 torture_param(int, shuffle_interval, 3,
  59              "Number of jiffies between shuffles, 0=disable");
  60 torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
  61 torture_param(int, stat_interval, 60,
  62              "Number of seconds between stats printk()s");
  63 torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
  64 torture_param(bool, verbose, true,
  65              "Enable verbose debugging printk()s");
  66
  67 static char *torture_type = "spin_lock";
  68 module_param(torture_type, charp, 0444);
  69 MODULE_PARM_DESC(torture_type,
  70                  "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
  71
  72 static atomic_t n_lock_torture_errors;
  73
  74 static struct task_struct *stats_task;
  75 static struct task_struct **writer_tasks;
  76
  77 static int nrealwriters_stress;
  78 static bool lock_is_write_held;
  79
  80 struct lock_writer_stress_stats {
  81         long n_write_lock_fail;
  82         long n_write_lock_acquired;
  83 };
  84 static struct lock_writer_stress_stats *lwsa;
  85
  86 #if defined(MODULE)
  87 #define LOCKTORTURE_RUNNABLE_INIT 1
  88 #else
  89 #define LOCKTORTURE_RUNNABLE_INIT 0
  90 #endif
  91 int torture_runnable = LOCKTORTURE_RUNNABLE_INIT;
  92 module_param(torture_runnable, int, 0444);
  93 MODULE_PARM_DESC(torture_runnable, "Start locktorture at module init");
  94
  95 /* Forward reference. */
  96 static void lock_torture_cleanup(void);
  97
  98 /*
  99  * Operations vector for selecting different types of tests.
 100  */
 101 struct lock_torture_ops {
 102         void (*init)(void);
 103         int (*writelock)(void);
 104         void (*write_delay)(struct torture_random_state *trsp);
 105         void (*writeunlock)(void);
 106         unsigned long flags;
 107         const char *name;
 108 };
 109
 110 static struct lock_torture_ops *cur_ops;
 111
 112 /*
 113  * Definitions for lock torture testing.
 114  */
 115
 116 static int torture_lock_busted_write_lock(void)
 117 {
 118         return 0;  /* BUGGY, do not use in real life!!! */
 119 }
 120
 121 static void torture_lock_busted_write_delay(struct torture_random_state *trsp)
 122 {
 123         const unsigned long longdelay_us = 100;
 124
 125         /* We want a long delay occasionally to force massive contention.  */
 126         if (!(torture_random(trsp) %
 127               (nrealwriters_stress * 2000 * longdelay_us)))
 128                 mdelay(longdelay_us);
 129 #ifdef CONFIG_PREEMPT
 130         if (!(torture_random(trsp) % (nrealwriters_stress * 20000)))
 131                 preempt_schedule();  /* Allow test to be preempted. */
 132 #endif
 133 }
 134
 135 static void torture_lock_busted_write_unlock(void)
 136 {
 137           /* BUGGY, do not use in real life!!! */
 138 }
 139
 140 static struct lock_torture_ops lock_busted_ops = {
 141         .writelock      = torture_lock_busted_write_lock,
 142         .write_delay    = torture_lock_busted_write_delay,
 143         .writeunlock    = torture_lock_busted_write_unlock,
 144         .name           = "lock_busted"
 145 };
 146
 147 static DEFINE_SPINLOCK(torture_spinlock);
 148
 149 static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock)
 150 {
 151         spin_lock(&torture_spinlock);
 152         return 0;
 153 }
 154
 155 static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
 156 {
 157         const unsigned long shortdelay_us = 2;
 158         const unsigned long longdelay_us = 100;
 159
 160         /* We want a short delay mostly to emulate likely code, and
 161          * we want a long delay occasionally to force massive contention.
 162          */
 163         if (!(torture_random(trsp) %
 164               (nrealwriters_stress * 2000 * longdelay_us)))
 165                 mdelay(longdelay_us);
 166         if (!(torture_random(trsp) %
 167               (nrealwriters_stress * 2 * shortdelay_us)))
 168                 udelay(shortdelay_us);
 169 #ifdef CONFIG_PREEMPT
 170         if (!(torture_random(trsp) % (nrealwriters_stress * 20000)))
 171                 preempt_schedule();  /* Allow test to be preempted. */
 172 #endif
 173 }
 174
 175 static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock)
 176 {
 177         spin_unlock(&torture_spinlock);
 178 }
 179
 180 static struct lock_torture_ops spin_lock_ops = {
 181         .writelock      = torture_spin_lock_write_lock,
 182         .write_delay    = torture_spin_lock_write_delay,
 183         .writeunlock    = torture_spin_lock_write_unlock,
 184         .name           = "spin_lock"
 185 };
 186
 187 static int torture_spin_lock_write_lock_irq(void)
 188 __acquires(torture_spinlock_irq)
 189 {
 190         unsigned long flags;
 191
 192         spin_lock_irqsave(&torture_spinlock, flags);
 193         cur_ops->flags = flags;
 194         return 0;
 195 }
 196
 197 static void torture_lock_spin_write_unlock_irq(void)
 198 __releases(torture_spinlock)
 199 {
 200         spin_unlock_irqrestore(&torture_spinlock, cur_ops->flags);
 201 }
 202
 203 static struct lock_torture_ops spin_lock_irq_ops = {
 204         .writelock      = torture_spin_lock_write_lock_irq,
 205         .write_delay    = torture_spin_lock_write_delay,
 206         .writeunlock    = torture_lock_spin_write_unlock_irq,
 207         .name           = "spin_lock_irq"
 208 };
 209
 210 static DEFINE_MUTEX(torture_mutex);
 211
 212 static int torture_mutex_lock(void) __acquires(torture_mutex)
 213 {
 214         mutex_lock(&torture_mutex);
 215         return 0;
 216 }
 217
 218 static void torture_mutex_delay(struct torture_random_state *trsp)
 219 {
 220         const unsigned long longdelay_ms = 100;
 221
 222         /* We want a long delay occasionally to force massive contention.  */
 223         if (!(torture_random(trsp) %
 224               (nrealwriters_stress * 2000 * longdelay_ms)))
 225                 mdelay(longdelay_ms * 5);
 226         else
 227                 mdelay(longdelay_ms / 5);
 228 #ifdef CONFIG_PREEMPT
 229         if (!(torture_random(trsp) % (nrealwriters_stress * 20000)))
 230                 preempt_schedule();  /* Allow test to be preempted. */
 231 #endif
 232 }
 233
 234 static void torture_mutex_unlock(void) __releases(torture_mutex)
 235 {
 236         mutex_unlock(&torture_mutex);
 237 }
 238
 239 static struct lock_torture_ops mutex_lock_ops = {
 240         .writelock      = torture_mutex_lock,
 241         .write_delay    = torture_mutex_delay,
 242         .writeunlock    = torture_mutex_unlock,
 243         .name           = "mutex_lock"
 244 };
 245
 246 /*
 247  * Lock torture writer kthread.  Repeatedly acquires and releases
 248  * the lock, checking for duplicate acquisitions.
 249  */
 250 static int lock_torture_writer(void *arg)
 251 {
 252         struct lock_writer_stress_stats *lwsp = arg;
 253         static DEFINE_TORTURE_RANDOM(rand);
 254
 255         VERBOSE_TOROUT_STRING("lock_torture_writer task started");
 256         set_user_nice(current, MAX_NICE);
 257
 258         do {
 259                 if ((torture_random(&rand) & 0xfffff) == 0)
 260                         schedule_timeout_uninterruptible(1);
 261                 cur_ops->writelock();
 262                 if (WARN_ON_ONCE(lock_is_write_held))
 263                         lwsp->n_write_lock_fail++;
 264                 lock_is_write_held = 1;
 265                 lwsp->n_write_lock_acquired++;
 266                 cur_ops->write_delay(&rand);
 267                 lock_is_write_held = 0;
 268                 cur_ops->writeunlock();
 269                 stutter_wait("lock_torture_writer");
 270         } while (!torture_must_stop());
 271         torture_kthread_stopping("lock_torture_writer");
 272         return 0;
 273 }
 274
 275 /*
 276  * Create an lock-torture-statistics message in the specified buffer.
 277  */
 278 static void lock_torture_printk(char *page)
 279 {
 280         bool fail = 0;
 281         int i;
 282         long max = 0;
 283         long min = lwsa[0].n_write_lock_acquired;
 284         long long sum = 0;
 285
 286         for (i = 0; i < nrealwriters_stress; i++) {
 287                 if (lwsa[i].n_write_lock_fail)
 288                         fail = true;
 289                 sum += lwsa[i].n_write_lock_acquired;
 290                 if (max < lwsa[i].n_write_lock_fail)
 291                         max = lwsa[i].n_write_lock_fail;
 292                 if (min > lwsa[i].n_write_lock_fail)
 293                         min = lwsa[i].n_write_lock_fail;
 294         }
 295         page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG);
 296         page += sprintf(page,
 297                         "Writes:  Total: %lld  Max/Min: %ld/%ld %s  Fail: %d %s\n",
 298                         sum, max, min, max / 2 > min ? "???" : "",
 299                         fail, fail ? "!!!" : "");
 300         if (fail)
 301                 atomic_inc(&n_lock_torture_errors);
 302 }
 303
 304 /*
 305  * Print torture statistics.  Caller must ensure that there is only one
 306  * call to this function at a given time!!!  This is normally accomplished
 307  * by relying on the module system to only have one copy of the module
 308  * loaded, and then by giving the lock_torture_stats kthread full control
 309  * (or the init/cleanup functions when lock_torture_stats thread is not
 310  * running).
 311  */
 312 static void lock_torture_stats_print(void)
 313 {
 314         int size = nrealwriters_stress * 200 + 8192;
 315         char *buf;
 316
 317         buf = kmalloc(size, GFP_KERNEL);
 318         if (!buf) {
 319                 pr_err("lock_torture_stats_print: Out of memory, need: %d",
 320                        size);
 321                 return;
 322         }
 323         lock_torture_printk(buf);
 324         pr_alert("%s", buf);
 325         kfree(buf);
 326 }
 327
 328 /*
 329  * Periodically prints torture statistics, if periodic statistics printing
 330  * was specified via the stat_interval module parameter.
 331  *
 332  * No need to worry about fullstop here, since this one doesn't reference
 333  * volatile state or register callbacks.
 334  */
 335 static int lock_torture_stats(void *arg)
 336 {
 337         VERBOSE_TOROUT_STRING("lock_torture_stats task started");
 338         do {
 339                 schedule_timeout_interruptible(stat_interval * HZ);
 340                 lock_torture_stats_print();
 341                 torture_shutdown_absorb("lock_torture_stats");
 342         } while (!torture_must_stop());
 343         torture_kthread_stopping("lock_torture_stats");
 344         return 0;
 345 }
 346
 347 static inline void
 348 lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
 349                                 const char *tag)
 350 {
 351         pr_alert("%s" TORTURE_FLAG
 352                  "--- %s: nwriters_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
 353                  torture_type, tag, nrealwriters_stress, stat_interval, verbose,
 354                  shuffle_interval, stutter, shutdown_secs,
 355                  onoff_interval, onoff_holdoff);
 356 }
 357
 358 static void lock_torture_cleanup(void)
 359 {
 360         int i;
 361
 362         if (torture_cleanup())
 363                 return;
 364
 365         if (writer_tasks) {
 366                 for (i = 0; i < nrealwriters_stress; i++)
 367                         torture_stop_kthread(lock_torture_writer,
 368                                              writer_tasks[i]);
 369                 kfree(writer_tasks);
 370                 writer_tasks = NULL;
 371         }
 372
 373         torture_stop_kthread(lock_torture_stats, stats_task);
 374         lock_torture_stats_print();  /* -After- the stats thread is stopped! */
 375
 376         if (atomic_read(&n_lock_torture_errors))
 377                 lock_torture_print_module_parms(cur_ops,
 378                                                 "End of test: FAILURE");
 379         else if (torture_onoff_failures())
 380                 lock_torture_print_module_parms(cur_ops,
 381                                                 "End of test: LOCK_HOTPLUG");
 382         else
 383                 lock_torture_print_module_parms(cur_ops,
 384                                                 "End of test: SUCCESS");
 385 }
 386
 387 static int __init lock_torture_init(void)
 388 {
 389         int i;
 390         int firsterr = 0;
 391         static struct lock_torture_ops *torture_ops[] = {
 392                 &lock_busted_ops, &spin_lock_ops, &spin_lock_irq_ops, &mutex_lock_ops,
 393         };
 394
 395         if (!torture_init_begin(torture_type, verbose, &torture_runnable))
 396                 return -EBUSY;
 397
 398         /* Process args and tell the world that the torturer is on the job. */
 399         for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
 400                 cur_ops = torture_ops[i];
 401                 if (strcmp(torture_type, cur_ops->name) == 0)
 402                         break;
 403         }
 404         if (i == ARRAY_SIZE(torture_ops)) {
 405                 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
 406                          torture_type);
 407                 pr_alert("lock-torture types:");
 408                 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
 409                         pr_alert(" %s", torture_ops[i]->name);
 410                 pr_alert("\n");
 411                 torture_init_end();
 412                 return -EINVAL;
 413         }
 414         if (cur_ops->init)
 415                 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
 416
 417         if (nwriters_stress >= 0)
 418                 nrealwriters_stress = nwriters_stress;
 419         else
 420                 nrealwriters_stress = 2 * num_online_cpus();
 421         lock_torture_print_module_parms(cur_ops, "Start of test");
 422
 423         /* Initialize the statistics so that each run gets its own numbers. */
 424
 425         lock_is_write_held = 0;
 426         lwsa = kmalloc(sizeof(*lwsa) * nrealwriters_stress, GFP_KERNEL);
 427         if (lwsa == NULL) {
 428                 VERBOSE_TOROUT_STRING("lwsa: Out of memory");
 429                 firsterr = -ENOMEM;
 430                 goto unwind;
 431         }
 432         for (i = 0; i < nrealwriters_stress; i++) {
 433                 lwsa[i].n_write_lock_fail = 0;
 434                 lwsa[i].n_write_lock_acquired = 0;
 435         }
 436
 437         /* Start up the kthreads. */
 438
 439         if (onoff_interval > 0) {
 440                 firsterr = torture_onoff_init(onoff_holdoff * HZ,
 441                                               onoff_interval * HZ);
 442                 if (firsterr)
 443                         goto unwind;
 444         }
 445         if (shuffle_interval > 0) {
 446                 firsterr = torture_shuffle_init(shuffle_interval);
 447                 if (firsterr)
 448                         goto unwind;
 449         }
 450         if (shutdown_secs > 0) {
 451                 firsterr = torture_shutdown_init(shutdown_secs,
 452                                                  lock_torture_cleanup);
 453                 if (firsterr)
 454                         goto unwind;
 455         }
 456         if (stutter > 0) {
 457                 firsterr = torture_stutter_init(stutter);
 458                 if (firsterr)
 459                         goto unwind;
 460         }
 461
 462         writer_tasks = kzalloc(nrealwriters_stress * sizeof(writer_tasks[0]),
 463                                GFP_KERNEL);
 464         if (writer_tasks == NULL) {
 465                 VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
 466                 firsterr = -ENOMEM;
 467                 goto unwind;
 468         }
 469         for (i = 0; i < nrealwriters_stress; i++) {
 470                 firsterr = torture_create_kthread(lock_torture_writer, &lwsa[i],
 471                                                   writer_tasks[i]);
 472                 if (firsterr)
 473                         goto unwind;
 474         }
 475         if (stat_interval > 0) {
 476                 firsterr = torture_create_kthread(lock_torture_stats, NULL,
 477                                                   stats_task);
 478                 if (firsterr)
 479                         goto unwind;
 480         }
 481         torture_init_end();
 482         return 0;
 483
 484 unwind:
 485         torture_init_end();
 486         lock_torture_cleanup();
 487         return firsterr;
 488 }
 489
 490 module_init(lock_torture_init);
 491 module_exit(lock_torture_cleanup);