lib/test_lockup.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Test module to generate lockups
   4  */
   5 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   6
   7 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <linux/delay.h>
  10 #include <linux/sched.h>
  11 #include <linux/sched/signal.h>
  12 #include <linux/sched/clock.h>
  13 #include <linux/cpu.h>
  14 #include <linux/nmi.h>
  15 #include <linux/mm.h>
  16 #include <linux/uaccess.h>
  17
  18 static unsigned int time_secs;
  19 module_param(time_secs, uint, 0600);
  20 MODULE_PARM_DESC(time_secs, "lockup time in seconds, default 0");
  21
  22 static unsigned int time_nsecs;
  23 module_param(time_nsecs, uint, 0600);
  24 MODULE_PARM_DESC(time_nsecs, "nanoseconds part of lockup time, default 0");
  25
  26 static unsigned int cooldown_secs;
  27 module_param(cooldown_secs, uint, 0600);
  28 MODULE_PARM_DESC(cooldown_secs, "cooldown time between iterations in seconds, default 0");
  29
  30 static unsigned int cooldown_nsecs;
  31 module_param(cooldown_nsecs, uint, 0600);
  32 MODULE_PARM_DESC(cooldown_nsecs, "nanoseconds part of cooldown, default 0");
  33
  34 static unsigned int iterations = 1;
  35 module_param(iterations, uint, 0600);
  36 MODULE_PARM_DESC(iterations, "lockup iterations, default 1");
  37
  38 static bool all_cpus;
  39 module_param(all_cpus, bool, 0400);
  40 MODULE_PARM_DESC(all_cpus, "trigger lockup at all cpus at once");
  41
  42 static int wait_state;
  43 static char *state = "R";
  44 module_param(state, charp, 0400);
  45 MODULE_PARM_DESC(state, "wait in 'R' running (default), 'D' uninterruptible, 'K' killable, 'S' interruptible state");
  46
  47 static bool use_hrtimer;
  48 module_param(use_hrtimer, bool, 0400);
  49 MODULE_PARM_DESC(use_hrtimer, "use high-resolution timer for sleeping");
  50
  51 static bool iowait;
  52 module_param(iowait, bool, 0400);
  53 MODULE_PARM_DESC(iowait, "account sleep time as iowait");
  54
  55 static bool lock_read;
  56 module_param(lock_read, bool, 0400);
  57 MODULE_PARM_DESC(lock_read, "lock read-write locks for read");
  58
  59 static bool lock_single;
  60 module_param(lock_single, bool, 0400);
  61 MODULE_PARM_DESC(lock_single, "acquire locks only at one cpu");
  62
  63 static bool reacquire_locks;
  64 module_param(reacquire_locks, bool, 0400);
  65 MODULE_PARM_DESC(reacquire_locks, "release and reacquire locks/irq/preempt between iterations");
  66
  67 static bool touch_softlockup;
  68 module_param(touch_softlockup, bool, 0600);
  69 MODULE_PARM_DESC(touch_softlockup, "touch soft-lockup watchdog between iterations");
  70
  71 static bool touch_hardlockup;
  72 module_param(touch_hardlockup, bool, 0600);
  73 MODULE_PARM_DESC(touch_hardlockup, "touch hard-lockup watchdog between iterations");
  74
  75 static bool call_cond_resched;
  76 module_param(call_cond_resched, bool, 0600);
  77 MODULE_PARM_DESC(call_cond_resched, "call cond_resched() between iterations");
  78
  79 static bool measure_lock_wait;
  80 module_param(measure_lock_wait, bool, 0400);
  81 MODULE_PARM_DESC(measure_lock_wait, "measure lock wait time");
  82
  83 static unsigned long lock_wait_threshold = ULONG_MAX;
  84 module_param(lock_wait_threshold, ulong, 0400);
  85 MODULE_PARM_DESC(lock_wait_threshold, "print lock wait time longer than this in nanoseconds, default off");
  86
  87 static bool test_disable_irq;
  88 module_param_named(disable_irq, test_disable_irq, bool, 0400);
  89 MODULE_PARM_DESC(disable_irq, "disable interrupts: generate hard-lockups");
  90
  91 static bool disable_softirq;
  92 module_param(disable_softirq, bool, 0400);
  93 MODULE_PARM_DESC(disable_softirq, "disable bottom-half irq handlers");
  94
  95 static bool disable_preempt;
  96 module_param(disable_preempt, bool, 0400);
  97 MODULE_PARM_DESC(disable_preempt, "disable preemption: generate soft-lockups");
  98
  99 static bool lock_rcu;
 100 module_param(lock_rcu, bool, 0400);
 101 MODULE_PARM_DESC(lock_rcu, "grab rcu_read_lock: generate rcu stalls");
 102
 103 static bool lock_mmap_sem;
 104 module_param(lock_mmap_sem, bool, 0400);
 105 MODULE_PARM_DESC(lock_mmap_sem, "lock mm->mmap_sem: block procfs interfaces");
 106
 107 static unsigned long lock_rwsem_ptr;
 108 module_param_unsafe(lock_rwsem_ptr, ulong, 0400);
 109 MODULE_PARM_DESC(lock_rwsem_ptr, "lock rw_semaphore at address");
 110
 111 static unsigned long lock_mutex_ptr;
 112 module_param_unsafe(lock_mutex_ptr, ulong, 0400);
 113 MODULE_PARM_DESC(lock_mutex_ptr, "lock mutex at address");
 114
 115 static unsigned long lock_spinlock_ptr;
 116 module_param_unsafe(lock_spinlock_ptr, ulong, 0400);
 117 MODULE_PARM_DESC(lock_spinlock_ptr, "lock spinlock at address");
 118
 119 static unsigned long lock_rwlock_ptr;
 120 module_param_unsafe(lock_rwlock_ptr, ulong, 0400);
 121 MODULE_PARM_DESC(lock_rwlock_ptr, "lock rwlock at address");
 122
 123 static unsigned int alloc_pages_nr;
 124 module_param_unsafe(alloc_pages_nr, uint, 0600);
 125 MODULE_PARM_DESC(alloc_pages_nr, "allocate and free pages under locks");
 126
 127 static unsigned int alloc_pages_order;
 128 module_param(alloc_pages_order, uint, 0400);
 129 MODULE_PARM_DESC(alloc_pages_order, "page order to allocate");
 130
 131 static gfp_t alloc_pages_gfp = GFP_KERNEL;
 132 module_param_unsafe(alloc_pages_gfp, uint, 0400);
 133 MODULE_PARM_DESC(alloc_pages_gfp, "allocate pages with this gfp_mask, default GFP_KERNEL");
 134
 135 static bool alloc_pages_atomic;
 136 module_param(alloc_pages_atomic, bool, 0400);
 137 MODULE_PARM_DESC(alloc_pages_atomic, "allocate pages with GFP_ATOMIC");
 138
 139 static bool reallocate_pages;
 140 module_param(reallocate_pages, bool, 0400);
 141 MODULE_PARM_DESC(reallocate_pages, "free and allocate pages between iterations");
 142
 143 static atomic_t alloc_pages_failed = ATOMIC_INIT(0);
 144
 145 static atomic64_t max_lock_wait = ATOMIC64_INIT(0);
 146
 147 static struct task_struct *main_task;
 148 static int master_cpu;
 149
 150 static void test_lock(bool master, bool verbose)
 151 {
 152         u64 uninitialized_var(wait_start);
 153
 154         if (measure_lock_wait)
 155                 wait_start = local_clock();
 156
 157         if (lock_mutex_ptr && master) {
 158                 if (verbose)
 159                         pr_notice("lock mutex %ps\n", (void *)lock_mutex_ptr);
 160                 mutex_lock((struct mutex *)lock_mutex_ptr);
 161         }
 162
 163         if (lock_rwsem_ptr && master) {
 164                 if (verbose)
 165                         pr_notice("lock rw_semaphore %ps\n",
 166                                   (void *)lock_rwsem_ptr);
 167                 if (lock_read)
 168                         down_read((struct rw_semaphore *)lock_rwsem_ptr);
 169                 else
 170                         down_write((struct rw_semaphore *)lock_rwsem_ptr);
 171         }
 172
 173         if (lock_mmap_sem && master) {
 174                 if (verbose)
 175                         pr_notice("lock mmap_sem pid=%d\n", main_task->pid);
 176                 if (lock_read)
 177                         down_read(&main_task->mm->mmap_sem);
 178                 else
 179                         down_write(&main_task->mm->mmap_sem);
 180         }
 181
 182         if (test_disable_irq)
 183                 local_irq_disable();
 184
 185         if (disable_softirq)
 186                 local_bh_disable();
 187
 188         if (disable_preempt)
 189                 preempt_disable();
 190
 191         if (lock_rcu)
 192                 rcu_read_lock();
 193
 194         if (lock_spinlock_ptr && master) {
 195                 if (verbose)
 196                         pr_notice("lock spinlock %ps\n",
 197                                   (void *)lock_spinlock_ptr);
 198                 spin_lock((spinlock_t *)lock_spinlock_ptr);
 199         }
 200
 201         if (lock_rwlock_ptr && master) {
 202                 if (verbose)
 203                         pr_notice("lock rwlock %ps\n",
 204                                   (void *)lock_rwlock_ptr);
 205                 if (lock_read)
 206                         read_lock((rwlock_t *)lock_rwlock_ptr);
 207                 else
 208                         write_lock((rwlock_t *)lock_rwlock_ptr);
 209         }
 210
 211         if (measure_lock_wait) {
 212                 s64 cur_wait = local_clock() - wait_start;
 213                 s64 max_wait = atomic64_read(&max_lock_wait);
 214
 215                 do {
 216                         if (cur_wait < max_wait)
 217                                 break;
 218                         max_wait = atomic64_cmpxchg(&max_lock_wait,
 219                                                     max_wait, cur_wait);
 220                 } while (max_wait != cur_wait);
 221
 222                 if (cur_wait > lock_wait_threshold)
 223                         pr_notice_ratelimited("lock wait %lld ns\n", cur_wait);
 224         }
 225 }
 226
 227 static void test_unlock(bool master, bool verbose)
 228 {
 229         if (lock_rwlock_ptr && master) {
 230                 if (lock_read)
 231                         read_unlock((rwlock_t *)lock_rwlock_ptr);
 232                 else
 233                         write_unlock((rwlock_t *)lock_rwlock_ptr);
 234                 if (verbose)
 235                         pr_notice("unlock rwlock %ps\n",
 236                                   (void *)lock_rwlock_ptr);
 237         }
 238
 239         if (lock_spinlock_ptr && master) {
 240                 spin_unlock((spinlock_t *)lock_spinlock_ptr);
 241                 if (verbose)
 242                         pr_notice("unlock spinlock %ps\n",
 243                                   (void *)lock_spinlock_ptr);
 244         }
 245
 246         if (lock_rcu)
 247                 rcu_read_unlock();
 248
 249         if (disable_preempt)
 250                 preempt_enable();
 251
 252         if (disable_softirq)
 253                 local_bh_enable();
 254
 255         if (test_disable_irq)
 256                 local_irq_enable();
 257
 258         if (lock_mmap_sem && master) {
 259                 if (lock_read)
 260                         up_read(&main_task->mm->mmap_sem);
 261                 else
 262                         up_write(&main_task->mm->mmap_sem);
 263                 if (verbose)
 264                         pr_notice("unlock mmap_sem pid=%d\n", main_task->pid);
 265         }
 266
 267         if (lock_rwsem_ptr && master) {
 268                 if (lock_read)
 269                         up_read((struct rw_semaphore *)lock_rwsem_ptr);
 270                 else
 271                         up_write((struct rw_semaphore *)lock_rwsem_ptr);
 272                 if (verbose)
 273                         pr_notice("unlock rw_semaphore %ps\n",
 274                                   (void *)lock_rwsem_ptr);
 275         }
 276
 277         if (lock_mutex_ptr && master) {
 278                 mutex_unlock((struct mutex *)lock_mutex_ptr);
 279                 if (verbose)
 280                         pr_notice("unlock mutex %ps\n",
 281                                   (void *)lock_mutex_ptr);
 282         }
 283 }
 284
 285 static void test_alloc_pages(struct list_head *pages)
 286 {
 287         struct page *page;
 288         unsigned int i;
 289
 290         for (i = 0; i < alloc_pages_nr; i++) {
 291                 page = alloc_pages(alloc_pages_gfp, alloc_pages_order);
 292                 if (!page) {
 293                         atomic_inc(&alloc_pages_failed);
 294                         break;
 295                 }
 296                 list_add(&page->lru, pages);
 297         }
 298 }
 299
 300 static void test_free_pages(struct list_head *pages)
 301 {
 302         struct page *page, *next;
 303
 304         list_for_each_entry_safe(page, next, pages, lru)
 305                 __free_pages(page, alloc_pages_order);
 306         INIT_LIST_HEAD(pages);
 307 }
 308
 309 static void test_wait(unsigned int secs, unsigned int nsecs)
 310 {
 311         if (wait_state == TASK_RUNNING) {
 312                 if (secs)
 313                         mdelay(secs * MSEC_PER_SEC);
 314                 if (nsecs)
 315                         ndelay(nsecs);
 316                 return;
 317         }
 318
 319         __set_current_state(wait_state);
 320         if (use_hrtimer) {
 321                 ktime_t time;
 322
 323                 time = ns_to_ktime((u64)secs * NSEC_PER_SEC + nsecs);
 324                 schedule_hrtimeout(&time, HRTIMER_MODE_REL);
 325         } else {
 326                 schedule_timeout(secs * HZ + nsecs_to_jiffies(nsecs));
 327         }
 328 }
 329
 330 static void test_lockup(bool master)
 331 {
 332         u64 lockup_start = local_clock();
 333         unsigned int iter = 0;
 334         LIST_HEAD(pages);
 335
 336         pr_notice("Start on CPU%d\n", raw_smp_processor_id());
 337
 338         test_lock(master, true);
 339
 340         test_alloc_pages(&pages);
 341
 342         while (iter++ < iterations && !signal_pending(main_task)) {
 343
 344                 if (iowait)
 345                         current->in_iowait = 1;
 346
 347                 test_wait(time_secs, time_nsecs);
 348
 349                 if (iowait)
 350                         current->in_iowait = 0;
 351
 352                 if (reallocate_pages)
 353                         test_free_pages(&pages);
 354
 355                 if (reacquire_locks)
 356                         test_unlock(master, false);
 357
 358                 if (touch_softlockup)
 359                         touch_softlockup_watchdog();
 360
 361                 if (touch_hardlockup)
 362                         touch_nmi_watchdog();
 363
 364                 if (call_cond_resched)
 365                         cond_resched();
 366
 367                 test_wait(cooldown_secs, cooldown_nsecs);
 368
 369                 if (reacquire_locks)
 370                         test_lock(master, false);
 371
 372                 if (reallocate_pages)
 373                         test_alloc_pages(&pages);
 374         }
 375
 376         pr_notice("Finish on CPU%d in %lld ns\n", raw_smp_processor_id(),
 377                   local_clock() - lockup_start);
 378
 379         test_free_pages(&pages);
 380
 381         test_unlock(master, true);
 382 }
 383
 384 DEFINE_PER_CPU(struct work_struct, test_works);
 385
 386 static void test_work_fn(struct work_struct *work)
 387 {
 388         test_lockup(!lock_single ||
 389                     work == per_cpu_ptr(&test_works, master_cpu));
 390 }
 391
 392 static bool test_kernel_ptr(unsigned long addr, int size)
 393 {
 394         void *ptr = (void *)addr;
 395         char buf;
 396
 397         if (!addr)
 398                 return false;
 399
 400         /* should be at least readable kernel address */
 401         if (access_ok(ptr, 1) ||
 402             access_ok(ptr + size - 1, 1) ||
 403             probe_kernel_address(ptr, buf) ||
 404             probe_kernel_address(ptr + size - 1, buf)) {
 405                 pr_err("invalid kernel ptr: %#lx\n", addr);
 406                 return true;
 407         }
 408
 409         return false;
 410 }
 411
 412 static bool __maybe_unused test_magic(unsigned long addr, int offset,
 413                                       unsigned int expected)
 414 {
 415         void *ptr = (void *)addr + offset;
 416         unsigned int magic = 0;
 417
 418         if (!addr)
 419                 return false;
 420
 421         if (probe_kernel_address(ptr, magic) || magic != expected) {
 422                 pr_err("invalid magic at %#lx + %#x = %#x, expected %#x\n",
 423                        addr, offset, magic, expected);
 424                 return true;
 425         }
 426
 427         return false;
 428 }
 429
 430 static int __init test_lockup_init(void)
 431 {
 432         u64 test_start = local_clock();
 433
 434         main_task = current;
 435
 436         switch (state[0]) {
 437         case 'S':
 438                 wait_state = TASK_INTERRUPTIBLE;
 439                 break;
 440         case 'D':
 441                 wait_state = TASK_UNINTERRUPTIBLE;
 442                 break;
 443         case 'K':
 444                 wait_state = TASK_KILLABLE;
 445                 break;
 446         case 'R':
 447                 wait_state = TASK_RUNNING;
 448                 break;
 449         default:
 450                 pr_err("unknown state=%s\n", state);
 451                 return -EINVAL;
 452         }
 453
 454         if (alloc_pages_atomic)
 455                 alloc_pages_gfp = GFP_ATOMIC;
 456
 457         if (test_kernel_ptr(lock_spinlock_ptr, sizeof(spinlock_t)) ||
 458             test_kernel_ptr(lock_rwlock_ptr, sizeof(rwlock_t)) ||
 459             test_kernel_ptr(lock_mutex_ptr, sizeof(struct mutex)) ||
 460             test_kernel_ptr(lock_rwsem_ptr, sizeof(struct rw_semaphore)))
 461                 return -EINVAL;
 462
 463 #ifdef CONFIG_DEBUG_SPINLOCK
 464         if (test_magic(lock_spinlock_ptr,
 465                        offsetof(spinlock_t, rlock.magic),
 466                        SPINLOCK_MAGIC) ||
 467             test_magic(lock_rwlock_ptr,
 468                        offsetof(rwlock_t, magic),
 469                        RWLOCK_MAGIC) ||
 470             test_magic(lock_mutex_ptr,
 471                        offsetof(struct mutex, wait_lock.rlock.magic),
 472                        SPINLOCK_MAGIC) ||
 473             test_magic(lock_rwsem_ptr,
 474                        offsetof(struct rw_semaphore, wait_lock.magic),
 475                        SPINLOCK_MAGIC))
 476                 return -EINVAL;
 477 #endif
 478
 479         if ((wait_state != TASK_RUNNING ||
 480              (call_cond_resched && !reacquire_locks) ||
 481              (alloc_pages_nr && gfpflags_allow_blocking(alloc_pages_gfp))) &&
 482             (test_disable_irq || disable_softirq || disable_preempt ||
 483              lock_rcu || lock_spinlock_ptr || lock_rwlock_ptr)) {
 484                 pr_err("refuse to sleep in atomic context\n");
 485                 return -EINVAL;
 486         }
 487
 488         if (lock_mmap_sem && !main_task->mm) {
 489                 pr_err("no mm to lock mmap_sem\n");
 490                 return -EINVAL;
 491         }
 492
 493         pr_notice("START pid=%d time=%u +%u ns cooldown=%u +%u ns iteraions=%u state=%s %s%s%s%s%s%s%s%s%s%s%s\n",
 494                   main_task->pid, time_secs, time_nsecs,
 495                   cooldown_secs, cooldown_nsecs, iterations, state,
 496                   all_cpus ? "all_cpus " : "",
 497                   iowait ? "iowait " : "",
 498                   test_disable_irq ? "disable_irq " : "",
 499                   disable_softirq ? "disable_softirq " : "",
 500                   disable_preempt ? "disable_preempt " : "",
 501                   lock_rcu ? "lock_rcu " : "",
 502                   lock_read ? "lock_read " : "",
 503                   touch_softlockup ? "touch_softlockup " : "",
 504                   touch_hardlockup ? "touch_hardlockup " : "",
 505                   call_cond_resched ? "call_cond_resched " : "",
 506                   reacquire_locks ? "reacquire_locks " : "");
 507
 508         if (alloc_pages_nr)
 509                 pr_notice("ALLOCATE PAGES nr=%u order=%u gfp=%pGg %s\n",
 510                           alloc_pages_nr, alloc_pages_order, &alloc_pages_gfp,
 511                           reallocate_pages ? "reallocate_pages " : "");
 512
 513         if (all_cpus) {
 514                 unsigned int cpu;
 515
 516                 cpus_read_lock();
 517
 518                 preempt_disable();
 519                 master_cpu = smp_processor_id();
 520                 for_each_online_cpu(cpu) {
 521                         INIT_WORK(per_cpu_ptr(&test_works, cpu), test_work_fn);
 522                         queue_work_on(cpu, system_highpri_wq,
 523                                       per_cpu_ptr(&test_works, cpu));
 524                 }
 525                 preempt_enable();
 526
 527                 for_each_online_cpu(cpu)
 528                         flush_work(per_cpu_ptr(&test_works, cpu));
 529
 530                 cpus_read_unlock();
 531         } else {
 532                 test_lockup(true);
 533         }
 534
 535         if (measure_lock_wait)
 536                 pr_notice("Maximum lock wait: %lld ns\n",
 537                           atomic64_read(&max_lock_wait));
 538
 539         if (alloc_pages_nr)
 540                 pr_notice("Page allocation failed %u times\n",
 541                           atomic_read(&alloc_pages_failed));
 542
 543         pr_notice("FINISH in %llu ns\n", local_clock() - test_start);
 544
 545         if (signal_pending(main_task))
 546                 return -EINTR;
 547
 548         return -EAGAIN;
 549 }
 550 module_init(test_lockup_init);
 551
 552 MODULE_LICENSE("GPL");
 553 MODULE_AUTHOR("Konstantin Khlebnikov <khlebnikov@yandex-team.ru>");
 554 MODULE_DESCRIPTION("Test module to generate lockups");