1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Common functions for in-kernel torture tests. 4 * 5 * Copyright (C) IBM Corporation, 2014 6 * 7 * Author: Paul E. McKenney <paulmck@linux.ibm.com> 8 * Based on kernel/rcu/torture.c. 9 */ 10 11 #define pr_fmt(fmt) fmt 12 13 #include <linux/types.h> 14 #include <linux/kernel.h> 15 #include <linux/init.h> 16 #include <linux/module.h> 17 #include <linux/kthread.h> 18 #include <linux/err.h> 19 #include <linux/spinlock.h> 20 #include <linux/smp.h> 21 #include <linux/interrupt.h> 22 #include <linux/sched.h> 23 #include <linux/sched/clock.h> 24 #include <linux/atomic.h> 25 #include <linux/bitops.h> 26 #include <linux/completion.h> 27 #include <linux/moduleparam.h> 28 #include <linux/percpu.h> 29 #include <linux/notifier.h> 30 #include <linux/reboot.h> 31 #include <linux/freezer.h> 32 #include <linux/cpu.h> 33 #include <linux/delay.h> 34 #include <linux/stat.h> 35 #include <linux/slab.h> 36 #include <linux/trace_clock.h> 37 #include <linux/ktime.h> 38 #include <asm/byteorder.h> 39 #include <linux/torture.h> 40 #include "rcu/rcu.h" 41 42 MODULE_LICENSE("GPL"); 43 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>"); 44 45 static bool disable_onoff_at_boot; 46 module_param(disable_onoff_at_boot, bool, 0444); 47 48 static bool ftrace_dump_at_shutdown; 49 module_param(ftrace_dump_at_shutdown, bool, 0444); 50 51 static int verbose_sleep_frequency; 52 module_param(verbose_sleep_frequency, int, 0444); 53 54 static int verbose_sleep_duration = 1; 55 module_param(verbose_sleep_duration, int, 0444); 56 57 static char *torture_type; 58 static int verbose; 59 60 /* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */ 61 #define FULLSTOP_DONTSTOP 0 /* Normal operation. */ 62 #define FULLSTOP_SHUTDOWN 1 /* System shutdown with torture running. */ 63 #define FULLSTOP_RMMOD 2 /* Normal rmmod of torture. */ 64 static int fullstop = FULLSTOP_RMMOD; 65 static DEFINE_MUTEX(fullstop_mutex); 66 67 static atomic_t verbose_sleep_counter; 68 69 /* 70 * Sleep if needed from VERBOSE_TOROUT*(). 71 */ 72 void verbose_torout_sleep(void) 73 { 74 if (verbose_sleep_frequency > 0 && 75 verbose_sleep_duration > 0 && 76 !(atomic_inc_return(&verbose_sleep_counter) % verbose_sleep_frequency)) 77 schedule_timeout_uninterruptible(verbose_sleep_duration); 78 } 79 EXPORT_SYMBOL_GPL(verbose_torout_sleep); 80 81 /* 82 * Schedule a high-resolution-timer sleep in nanoseconds, with a 32-bit 83 * nanosecond random fuzz. This function and its friends desynchronize 84 * testing from the timer wheel. 85 */ 86 int torture_hrtimeout_ns(ktime_t baset_ns, u32 fuzzt_ns, struct torture_random_state *trsp) 87 { 88 ktime_t hto = baset_ns; 89 90 if (trsp) 91 hto += (torture_random(trsp) >> 3) % fuzzt_ns; 92 set_current_state(TASK_UNINTERRUPTIBLE); 93 return schedule_hrtimeout(&hto, HRTIMER_MODE_REL); 94 } 95 EXPORT_SYMBOL_GPL(torture_hrtimeout_ns); 96 97 /* 98 * Schedule a high-resolution-timer sleep in microseconds, with a 32-bit 99 * nanosecond (not microsecond!) random fuzz. 100 */ 101 int torture_hrtimeout_us(u32 baset_us, u32 fuzzt_ns, struct torture_random_state *trsp) 102 { 103 ktime_t baset_ns = baset_us * NSEC_PER_USEC; 104 105 return torture_hrtimeout_ns(baset_ns, fuzzt_ns, trsp); 106 } 107 EXPORT_SYMBOL_GPL(torture_hrtimeout_us); 108 109 /* 110 * Schedule a high-resolution-timer sleep in milliseconds, with a 32-bit 111 * microsecond (not millisecond!) random fuzz. 112 */ 113 int torture_hrtimeout_ms(u32 baset_ms, u32 fuzzt_us, struct torture_random_state *trsp) 114 { 115 ktime_t baset_ns = baset_ms * NSEC_PER_MSEC; 116 u32 fuzzt_ns; 117 118 if ((u32)~0U / NSEC_PER_USEC < fuzzt_us) 119 fuzzt_ns = (u32)~0U; 120 else 121 fuzzt_ns = fuzzt_us * NSEC_PER_USEC; 122 return torture_hrtimeout_ns(baset_ns, fuzzt_ns, trsp); 123 } 124 EXPORT_SYMBOL_GPL(torture_hrtimeout_ms); 125 126 /* 127 * Schedule a high-resolution-timer sleep in jiffies, with an 128 * implied one-jiffy random fuzz. This is intended to replace calls to 129 * schedule_timeout_interruptible() and friends. 130 */ 131 int torture_hrtimeout_jiffies(u32 baset_j, struct torture_random_state *trsp) 132 { 133 ktime_t baset_ns = jiffies_to_nsecs(baset_j); 134 135 return torture_hrtimeout_ns(baset_ns, jiffies_to_nsecs(1), trsp); 136 } 137 EXPORT_SYMBOL_GPL(torture_hrtimeout_jiffies); 138 139 /* 140 * Schedule a high-resolution-timer sleep in milliseconds, with a 32-bit 141 * millisecond (not second!) random fuzz. 142 */ 143 int torture_hrtimeout_s(u32 baset_s, u32 fuzzt_ms, struct torture_random_state *trsp) 144 { 145 ktime_t baset_ns = baset_s * NSEC_PER_SEC; 146 u32 fuzzt_ns; 147 148 if ((u32)~0U / NSEC_PER_MSEC < fuzzt_ms) 149 fuzzt_ns = (u32)~0U; 150 else 151 fuzzt_ns = fuzzt_ms * NSEC_PER_MSEC; 152 return torture_hrtimeout_ns(baset_ns, fuzzt_ns, trsp); 153 } 154 EXPORT_SYMBOL_GPL(torture_hrtimeout_s); 155 156 #ifdef CONFIG_HOTPLUG_CPU 157 158 /* 159 * Variables for online-offline handling. Only present if CPU hotplug 160 * is enabled, otherwise does nothing. 161 */ 162 163 static struct task_struct *onoff_task; 164 static long onoff_holdoff; 165 static long onoff_interval; 166 static torture_ofl_func *onoff_f; 167 static long n_offline_attempts; 168 static long n_offline_successes; 169 static unsigned long sum_offline; 170 static int min_offline = -1; 171 static int max_offline; 172 static long n_online_attempts; 173 static long n_online_successes; 174 static unsigned long sum_online; 175 static int min_online = -1; 176 static int max_online; 177 178 /* 179 * Attempt to take a CPU offline. Return false if the CPU is already 180 * offline or if it is not subject to CPU-hotplug operations. The 181 * caller can detect other failures by looking at the statistics. 182 */ 183 bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes, 184 unsigned long *sum_offl, int *min_offl, int *max_offl) 185 { 186 unsigned long delta; 187 int ret; 188 char *s; 189 unsigned long starttime; 190 191 if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu)) 192 return false; 193 if (num_online_cpus() <= 1) 194 return false; /* Can't offline the last CPU. */ 195 196 if (verbose > 1) 197 pr_alert("%s" TORTURE_FLAG 198 "torture_onoff task: offlining %d\n", 199 torture_type, cpu); 200 starttime = jiffies; 201 (*n_offl_attempts)++; 202 ret = remove_cpu(cpu); 203 if (ret) { 204 s = ""; 205 if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) { 206 // PCI probe frequently disables hotplug during boot. 207 (*n_offl_attempts)--; 208 s = " (-EBUSY forgiven during boot)"; 209 } 210 if (verbose) 211 pr_alert("%s" TORTURE_FLAG 212 "torture_onoff task: offline %d failed%s: errno %d\n", 213 torture_type, cpu, s, ret); 214 } else { 215 if (verbose > 1) 216 pr_alert("%s" TORTURE_FLAG 217 "torture_onoff task: offlined %d\n", 218 torture_type, cpu); 219 if (onoff_f) 220 onoff_f(); 221 (*n_offl_successes)++; 222 delta = jiffies - starttime; 223 *sum_offl += delta; 224 if (*min_offl < 0) { 225 *min_offl = delta; 226 *max_offl = delta; 227 } 228 if (*min_offl > delta) 229 *min_offl = delta; 230 if (*max_offl < delta) 231 *max_offl = delta; 232 } 233 234 return true; 235 } 236 EXPORT_SYMBOL_GPL(torture_offline); 237 238 /* 239 * Attempt to bring a CPU online. Return false if the CPU is already 240 * online or if it is not subject to CPU-hotplug operations. The 241 * caller can detect other failures by looking at the statistics. 242 */ 243 bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes, 244 unsigned long *sum_onl, int *min_onl, int *max_onl) 245 { 246 unsigned long delta; 247 int ret; 248 char *s; 249 unsigned long starttime; 250 251 if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu)) 252 return false; 253 254 if (verbose > 1) 255 pr_alert("%s" TORTURE_FLAG 256 "torture_onoff task: onlining %d\n", 257 torture_type, cpu); 258 starttime = jiffies; 259 (*n_onl_attempts)++; 260 ret = add_cpu(cpu); 261 if (ret) { 262 s = ""; 263 if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) { 264 // PCI probe frequently disables hotplug during boot. 265 (*n_onl_attempts)--; 266 s = " (-EBUSY forgiven during boot)"; 267 } 268 if (verbose) 269 pr_alert("%s" TORTURE_FLAG 270 "torture_onoff task: online %d failed%s: errno %d\n", 271 torture_type, cpu, s, ret); 272 } else { 273 if (verbose > 1) 274 pr_alert("%s" TORTURE_FLAG 275 "torture_onoff task: onlined %d\n", 276 torture_type, cpu); 277 (*n_onl_successes)++; 278 delta = jiffies - starttime; 279 *sum_onl += delta; 280 if (*min_onl < 0) { 281 *min_onl = delta; 282 *max_onl = delta; 283 } 284 if (*min_onl > delta) 285 *min_onl = delta; 286 if (*max_onl < delta) 287 *max_onl = delta; 288 } 289 290 return true; 291 } 292 EXPORT_SYMBOL_GPL(torture_online); 293 294 /* 295 * Get everything online at the beginning and ends of tests. 296 */ 297 static void torture_online_all(char *phase) 298 { 299 int cpu; 300 int ret; 301 302 for_each_possible_cpu(cpu) { 303 if (cpu_online(cpu)) 304 continue; 305 ret = add_cpu(cpu); 306 if (ret && verbose) { 307 pr_alert("%s" TORTURE_FLAG 308 "%s: %s online %d: errno %d\n", 309 __func__, phase, torture_type, cpu, ret); 310 } 311 } 312 } 313 314 /* 315 * Execute random CPU-hotplug operations at the interval specified 316 * by the onoff_interval. 317 */ 318 static int 319 torture_onoff(void *arg) 320 { 321 int cpu; 322 int maxcpu = -1; 323 DEFINE_TORTURE_RANDOM(rand); 324 325 VERBOSE_TOROUT_STRING("torture_onoff task started"); 326 for_each_online_cpu(cpu) 327 maxcpu = cpu; 328 WARN_ON(maxcpu < 0); 329 torture_online_all("Initial"); 330 if (maxcpu == 0) { 331 VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled"); 332 goto stop; 333 } 334 335 if (onoff_holdoff > 0) { 336 VERBOSE_TOROUT_STRING("torture_onoff begin holdoff"); 337 schedule_timeout_interruptible(onoff_holdoff); 338 VERBOSE_TOROUT_STRING("torture_onoff end holdoff"); 339 } 340 while (!torture_must_stop()) { 341 if (disable_onoff_at_boot && !rcu_inkernel_boot_has_ended()) { 342 schedule_timeout_interruptible(HZ / 10); 343 continue; 344 } 345 cpu = (torture_random(&rand) >> 4) % (maxcpu + 1); 346 if (!torture_offline(cpu, 347 &n_offline_attempts, &n_offline_successes, 348 &sum_offline, &min_offline, &max_offline)) 349 torture_online(cpu, 350 &n_online_attempts, &n_online_successes, 351 &sum_online, &min_online, &max_online); 352 schedule_timeout_interruptible(onoff_interval); 353 } 354 355 stop: 356 torture_kthread_stopping("torture_onoff"); 357 torture_online_all("Final"); 358 return 0; 359 } 360 361 #endif /* #ifdef CONFIG_HOTPLUG_CPU */ 362 363 /* 364 * Initiate online-offline handling. 365 */ 366 int torture_onoff_init(long ooholdoff, long oointerval, torture_ofl_func *f) 367 { 368 #ifdef CONFIG_HOTPLUG_CPU 369 onoff_holdoff = ooholdoff; 370 onoff_interval = oointerval; 371 onoff_f = f; 372 if (onoff_interval <= 0) 373 return 0; 374 return torture_create_kthread(torture_onoff, NULL, onoff_task); 375 #else /* #ifdef CONFIG_HOTPLUG_CPU */ 376 return 0; 377 #endif /* #else #ifdef CONFIG_HOTPLUG_CPU */ 378 } 379 EXPORT_SYMBOL_GPL(torture_onoff_init); 380 381 /* 382 * Clean up after online/offline testing. 383 */ 384 static void torture_onoff_cleanup(void) 385 { 386 #ifdef CONFIG_HOTPLUG_CPU 387 if (onoff_task == NULL) 388 return; 389 VERBOSE_TOROUT_STRING("Stopping torture_onoff task"); 390 kthread_stop(onoff_task); 391 onoff_task = NULL; 392 #endif /* #ifdef CONFIG_HOTPLUG_CPU */ 393 } 394 395 /* 396 * Print online/offline testing statistics. 397 */ 398 void torture_onoff_stats(void) 399 { 400 #ifdef CONFIG_HOTPLUG_CPU 401 pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ", 402 n_online_successes, n_online_attempts, 403 n_offline_successes, n_offline_attempts, 404 min_online, max_online, 405 min_offline, max_offline, 406 sum_online, sum_offline, HZ); 407 #endif /* #ifdef CONFIG_HOTPLUG_CPU */ 408 } 409 EXPORT_SYMBOL_GPL(torture_onoff_stats); 410 411 /* 412 * Were all the online/offline operations successful? 413 */ 414 bool torture_onoff_failures(void) 415 { 416 #ifdef CONFIG_HOTPLUG_CPU 417 return n_online_successes != n_online_attempts || 418 n_offline_successes != n_offline_attempts; 419 #else /* #ifdef CONFIG_HOTPLUG_CPU */ 420 return false; 421 #endif /* #else #ifdef CONFIG_HOTPLUG_CPU */ 422 } 423 EXPORT_SYMBOL_GPL(torture_onoff_failures); 424 425 #define TORTURE_RANDOM_MULT 39916801 /* prime */ 426 #define TORTURE_RANDOM_ADD 479001701 /* prime */ 427 #define TORTURE_RANDOM_REFRESH 10000 428 429 /* 430 * Crude but fast random-number generator. Uses a linear congruential 431 * generator, with occasional help from cpu_clock(). 432 */ 433 unsigned long 434 torture_random(struct torture_random_state *trsp) 435 { 436 if (--trsp->trs_count < 0) { 437 trsp->trs_state += (unsigned long)local_clock(); 438 trsp->trs_count = TORTURE_RANDOM_REFRESH; 439 } 440 trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT + 441 TORTURE_RANDOM_ADD; 442 return swahw32(trsp->trs_state); 443 } 444 EXPORT_SYMBOL_GPL(torture_random); 445 446 /* 447 * Variables for shuffling. The idea is to ensure that each CPU stays 448 * idle for an extended period to test interactions with dyntick idle, 449 * as well as interactions with any per-CPU variables. 450 */ 451 struct shuffle_task { 452 struct list_head st_l; 453 struct task_struct *st_t; 454 }; 455 456 static long shuffle_interval; /* In jiffies. */ 457 static struct task_struct *shuffler_task; 458 static cpumask_var_t shuffle_tmp_mask; 459 static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */ 460 static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list); 461 static DEFINE_MUTEX(shuffle_task_mutex); 462 463 /* 464 * Register a task to be shuffled. If there is no memory, just splat 465 * and don't bother registering. 466 */ 467 void torture_shuffle_task_register(struct task_struct *tp) 468 { 469 struct shuffle_task *stp; 470 471 if (WARN_ON_ONCE(tp == NULL)) 472 return; 473 stp = kmalloc(sizeof(*stp), GFP_KERNEL); 474 if (WARN_ON_ONCE(stp == NULL)) 475 return; 476 stp->st_t = tp; 477 mutex_lock(&shuffle_task_mutex); 478 list_add(&stp->st_l, &shuffle_task_list); 479 mutex_unlock(&shuffle_task_mutex); 480 } 481 EXPORT_SYMBOL_GPL(torture_shuffle_task_register); 482 483 /* 484 * Unregister all tasks, for example, at the end of the torture run. 485 */ 486 static void torture_shuffle_task_unregister_all(void) 487 { 488 struct shuffle_task *stp; 489 struct shuffle_task *p; 490 491 mutex_lock(&shuffle_task_mutex); 492 list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) { 493 list_del(&stp->st_l); 494 kfree(stp); 495 } 496 mutex_unlock(&shuffle_task_mutex); 497 } 498 499 /* Shuffle tasks such that we allow shuffle_idle_cpu to become idle. 500 * A special case is when shuffle_idle_cpu = -1, in which case we allow 501 * the tasks to run on all CPUs. 502 */ 503 static void torture_shuffle_tasks(void) 504 { 505 struct shuffle_task *stp; 506 507 cpumask_setall(shuffle_tmp_mask); 508 get_online_cpus(); 509 510 /* No point in shuffling if there is only one online CPU (ex: UP) */ 511 if (num_online_cpus() == 1) { 512 put_online_cpus(); 513 return; 514 } 515 516 /* Advance to the next CPU. Upon overflow, don't idle any CPUs. */ 517 shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask); 518 if (shuffle_idle_cpu >= nr_cpu_ids) 519 shuffle_idle_cpu = -1; 520 else 521 cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask); 522 523 mutex_lock(&shuffle_task_mutex); 524 list_for_each_entry(stp, &shuffle_task_list, st_l) 525 set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask); 526 mutex_unlock(&shuffle_task_mutex); 527 528 put_online_cpus(); 529 } 530 531 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the 532 * system to become idle at a time and cut off its timer ticks. This is meant 533 * to test the support for such tickless idle CPU in RCU. 534 */ 535 static int torture_shuffle(void *arg) 536 { 537 VERBOSE_TOROUT_STRING("torture_shuffle task started"); 538 do { 539 schedule_timeout_interruptible(shuffle_interval); 540 torture_shuffle_tasks(); 541 torture_shutdown_absorb("torture_shuffle"); 542 } while (!torture_must_stop()); 543 torture_kthread_stopping("torture_shuffle"); 544 return 0; 545 } 546 547 /* 548 * Start the shuffler, with shuffint in jiffies. 549 */ 550 int torture_shuffle_init(long shuffint) 551 { 552 shuffle_interval = shuffint; 553 554 shuffle_idle_cpu = -1; 555 556 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) { 557 VERBOSE_TOROUT_ERRSTRING("Failed to alloc mask"); 558 return -ENOMEM; 559 } 560 561 /* Create the shuffler thread */ 562 return torture_create_kthread(torture_shuffle, NULL, shuffler_task); 563 } 564 EXPORT_SYMBOL_GPL(torture_shuffle_init); 565 566 /* 567 * Stop the shuffling. 568 */ 569 static void torture_shuffle_cleanup(void) 570 { 571 torture_shuffle_task_unregister_all(); 572 if (shuffler_task) { 573 VERBOSE_TOROUT_STRING("Stopping torture_shuffle task"); 574 kthread_stop(shuffler_task); 575 free_cpumask_var(shuffle_tmp_mask); 576 } 577 shuffler_task = NULL; 578 } 579 580 /* 581 * Variables for auto-shutdown. This allows "lights out" torture runs 582 * to be fully scripted. 583 */ 584 static struct task_struct *shutdown_task; 585 static ktime_t shutdown_time; /* time to system shutdown. */ 586 static void (*torture_shutdown_hook)(void); 587 588 /* 589 * Absorb kthreads into a kernel function that won't return, so that 590 * they won't ever access module text or data again. 591 */ 592 void torture_shutdown_absorb(const char *title) 593 { 594 while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) { 595 pr_notice("torture thread %s parking due to system shutdown\n", 596 title); 597 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT); 598 } 599 } 600 EXPORT_SYMBOL_GPL(torture_shutdown_absorb); 601 602 /* 603 * Cause the torture test to shutdown the system after the test has 604 * run for the time specified by the shutdown_secs parameter. 605 */ 606 static int torture_shutdown(void *arg) 607 { 608 ktime_t ktime_snap; 609 610 VERBOSE_TOROUT_STRING("torture_shutdown task started"); 611 ktime_snap = ktime_get(); 612 while (ktime_before(ktime_snap, shutdown_time) && 613 !torture_must_stop()) { 614 if (verbose) 615 pr_alert("%s" TORTURE_FLAG 616 "torture_shutdown task: %llu ms remaining\n", 617 torture_type, 618 ktime_ms_delta(shutdown_time, ktime_snap)); 619 set_current_state(TASK_INTERRUPTIBLE); 620 schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS); 621 ktime_snap = ktime_get(); 622 } 623 if (torture_must_stop()) { 624 torture_kthread_stopping("torture_shutdown"); 625 return 0; 626 } 627 628 /* OK, shut down the system. */ 629 630 VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system"); 631 shutdown_task = NULL; /* Avoid self-kill deadlock. */ 632 if (torture_shutdown_hook) 633 torture_shutdown_hook(); 634 else 635 VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping."); 636 if (ftrace_dump_at_shutdown) 637 rcu_ftrace_dump(DUMP_ALL); 638 kernel_power_off(); /* Shut down the system. */ 639 return 0; 640 } 641 642 /* 643 * Start up the shutdown task. 644 */ 645 int torture_shutdown_init(int ssecs, void (*cleanup)(void)) 646 { 647 torture_shutdown_hook = cleanup; 648 if (ssecs > 0) { 649 shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0)); 650 return torture_create_kthread(torture_shutdown, NULL, 651 shutdown_task); 652 } 653 return 0; 654 } 655 EXPORT_SYMBOL_GPL(torture_shutdown_init); 656 657 /* 658 * Detect and respond to a system shutdown. 659 */ 660 static int torture_shutdown_notify(struct notifier_block *unused1, 661 unsigned long unused2, void *unused3) 662 { 663 mutex_lock(&fullstop_mutex); 664 if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) { 665 VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected"); 666 WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN); 667 } else { 668 pr_warn("Concurrent rmmod and shutdown illegal!\n"); 669 } 670 mutex_unlock(&fullstop_mutex); 671 return NOTIFY_DONE; 672 } 673 674 static struct notifier_block torture_shutdown_nb = { 675 .notifier_call = torture_shutdown_notify, 676 }; 677 678 /* 679 * Shut down the shutdown task. Say what??? Heh! This can happen if 680 * the torture module gets an rmmod before the shutdown time arrives. ;-) 681 */ 682 static void torture_shutdown_cleanup(void) 683 { 684 unregister_reboot_notifier(&torture_shutdown_nb); 685 if (shutdown_task != NULL) { 686 VERBOSE_TOROUT_STRING("Stopping torture_shutdown task"); 687 kthread_stop(shutdown_task); 688 } 689 shutdown_task = NULL; 690 } 691 692 /* 693 * Variables for stuttering, which means to periodically pause and 694 * restart testing in order to catch bugs that appear when load is 695 * suddenly applied to or removed from the system. 696 */ 697 static struct task_struct *stutter_task; 698 static int stutter_pause_test; 699 static int stutter; 700 static int stutter_gap; 701 702 /* 703 * Block until the stutter interval ends. This must be called periodically 704 * by all running kthreads that need to be subject to stuttering. 705 */ 706 bool stutter_wait(const char *title) 707 { 708 unsigned int i = 0; 709 bool ret = false; 710 int spt; 711 712 cond_resched_tasks_rcu_qs(); 713 spt = READ_ONCE(stutter_pause_test); 714 for (; spt; spt = READ_ONCE(stutter_pause_test)) { 715 if (!ret) { 716 sched_set_normal(current, MAX_NICE); 717 ret = true; 718 } 719 if (spt == 1) { 720 schedule_timeout_interruptible(1); 721 } else if (spt == 2) { 722 while (READ_ONCE(stutter_pause_test)) { 723 if (!(i++ & 0xffff)) 724 torture_hrtimeout_us(10, 0, NULL); 725 cond_resched(); 726 } 727 } else { 728 schedule_timeout_interruptible(round_jiffies_relative(HZ)); 729 } 730 torture_shutdown_absorb(title); 731 } 732 return ret; 733 } 734 EXPORT_SYMBOL_GPL(stutter_wait); 735 736 /* 737 * Cause the torture test to "stutter", starting and stopping all 738 * threads periodically. 739 */ 740 static int torture_stutter(void *arg) 741 { 742 DEFINE_TORTURE_RANDOM(rand); 743 int wtime; 744 745 VERBOSE_TOROUT_STRING("torture_stutter task started"); 746 do { 747 if (!torture_must_stop() && stutter > 1) { 748 wtime = stutter; 749 if (stutter > 2) { 750 WRITE_ONCE(stutter_pause_test, 1); 751 wtime = stutter - 3; 752 torture_hrtimeout_jiffies(wtime, &rand); 753 wtime = 2; 754 } 755 WRITE_ONCE(stutter_pause_test, 2); 756 torture_hrtimeout_jiffies(wtime, NULL); 757 } 758 WRITE_ONCE(stutter_pause_test, 0); 759 if (!torture_must_stop()) 760 torture_hrtimeout_jiffies(stutter_gap, NULL); 761 torture_shutdown_absorb("torture_stutter"); 762 } while (!torture_must_stop()); 763 torture_kthread_stopping("torture_stutter"); 764 return 0; 765 } 766 767 /* 768 * Initialize and kick off the torture_stutter kthread. 769 */ 770 int torture_stutter_init(const int s, const int sgap) 771 { 772 stutter = s; 773 stutter_gap = sgap; 774 return torture_create_kthread(torture_stutter, NULL, stutter_task); 775 } 776 EXPORT_SYMBOL_GPL(torture_stutter_init); 777 778 /* 779 * Cleanup after the torture_stutter kthread. 780 */ 781 static void torture_stutter_cleanup(void) 782 { 783 if (!stutter_task) 784 return; 785 VERBOSE_TOROUT_STRING("Stopping torture_stutter task"); 786 kthread_stop(stutter_task); 787 stutter_task = NULL; 788 } 789 790 /* 791 * Initialize torture module. Please note that this is -not- invoked via 792 * the usual module_init() mechanism, but rather by an explicit call from 793 * the client torture module. This call must be paired with a later 794 * torture_init_end(). 795 * 796 * The runnable parameter points to a flag that controls whether or not 797 * the test is currently runnable. If there is no such flag, pass in NULL. 798 */ 799 bool torture_init_begin(char *ttype, int v) 800 { 801 mutex_lock(&fullstop_mutex); 802 if (torture_type != NULL) { 803 pr_alert("torture_init_begin: Refusing %s init: %s running.\n", 804 ttype, torture_type); 805 pr_alert("torture_init_begin: One torture test at a time!\n"); 806 mutex_unlock(&fullstop_mutex); 807 return false; 808 } 809 torture_type = ttype; 810 verbose = v; 811 fullstop = FULLSTOP_DONTSTOP; 812 return true; 813 } 814 EXPORT_SYMBOL_GPL(torture_init_begin); 815 816 /* 817 * Tell the torture module that initialization is complete. 818 */ 819 void torture_init_end(void) 820 { 821 mutex_unlock(&fullstop_mutex); 822 register_reboot_notifier(&torture_shutdown_nb); 823 } 824 EXPORT_SYMBOL_GPL(torture_init_end); 825 826 /* 827 * Clean up torture module. Please note that this is -not- invoked via 828 * the usual module_exit() mechanism, but rather by an explicit call from 829 * the client torture module. Returns true if a race with system shutdown 830 * is detected, otherwise, all kthreads started by functions in this file 831 * will be shut down. 832 * 833 * This must be called before the caller starts shutting down its own 834 * kthreads. 835 * 836 * Both torture_cleanup_begin() and torture_cleanup_end() must be paired, 837 * in order to correctly perform the cleanup. They are separated because 838 * threads can still need to reference the torture_type type, thus nullify 839 * only after completing all other relevant calls. 840 */ 841 bool torture_cleanup_begin(void) 842 { 843 mutex_lock(&fullstop_mutex); 844 if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) { 845 pr_warn("Concurrent rmmod and shutdown illegal!\n"); 846 mutex_unlock(&fullstop_mutex); 847 schedule_timeout_uninterruptible(10); 848 return true; 849 } 850 WRITE_ONCE(fullstop, FULLSTOP_RMMOD); 851 mutex_unlock(&fullstop_mutex); 852 torture_shutdown_cleanup(); 853 torture_shuffle_cleanup(); 854 torture_stutter_cleanup(); 855 torture_onoff_cleanup(); 856 return false; 857 } 858 EXPORT_SYMBOL_GPL(torture_cleanup_begin); 859 860 void torture_cleanup_end(void) 861 { 862 mutex_lock(&fullstop_mutex); 863 torture_type = NULL; 864 mutex_unlock(&fullstop_mutex); 865 } 866 EXPORT_SYMBOL_GPL(torture_cleanup_end); 867 868 /* 869 * Is it time for the current torture test to stop? 870 */ 871 bool torture_must_stop(void) 872 { 873 return torture_must_stop_irq() || kthread_should_stop(); 874 } 875 EXPORT_SYMBOL_GPL(torture_must_stop); 876 877 /* 878 * Is it time for the current torture test to stop? This is the irq-safe 879 * version, hence no check for kthread_should_stop(). 880 */ 881 bool torture_must_stop_irq(void) 882 { 883 return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP; 884 } 885 EXPORT_SYMBOL_GPL(torture_must_stop_irq); 886 887 /* 888 * Each kthread must wait for kthread_should_stop() before returning from 889 * its top-level function, otherwise segfaults ensue. This function 890 * prints a "stopping" message and waits for kthread_should_stop(), and 891 * should be called from all torture kthreads immediately prior to 892 * returning. 893 */ 894 void torture_kthread_stopping(char *title) 895 { 896 char buf[128]; 897 898 snprintf(buf, sizeof(buf), "Stopping %s", title); 899 VERBOSE_TOROUT_STRING(buf); 900 while (!kthread_should_stop()) { 901 torture_shutdown_absorb(title); 902 schedule_timeout_uninterruptible(1); 903 } 904 } 905 EXPORT_SYMBOL_GPL(torture_kthread_stopping); 906 907 /* 908 * Create a generic torture kthread that is immediately runnable. If you 909 * need the kthread to be stopped so that you can do something to it before 910 * it starts, you will need to open-code your own. 911 */ 912 int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m, 913 char *f, struct task_struct **tp) 914 { 915 int ret = 0; 916 917 VERBOSE_TOROUT_STRING(m); 918 *tp = kthread_run(fn, arg, "%s", s); 919 if (IS_ERR(*tp)) { 920 ret = PTR_ERR(*tp); 921 VERBOSE_TOROUT_ERRSTRING(f); 922 *tp = NULL; 923 } 924 torture_shuffle_task_register(*tp); 925 return ret; 926 } 927 EXPORT_SYMBOL_GPL(_torture_create_kthread); 928 929 /* 930 * Stop a generic kthread, emitting a message. 931 */ 932 void _torture_stop_kthread(char *m, struct task_struct **tp) 933 { 934 if (*tp == NULL) 935 return; 936 VERBOSE_TOROUT_STRING(m); 937 kthread_stop(*tp); 938 *tp = NULL; 939 } 940 EXPORT_SYMBOL_GPL(_torture_stop_kthread); 941