621 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Test module to generate lockups4 */5#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt6 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#include <linux/file.h>18 19static unsigned int time_secs;20module_param(time_secs, uint, 0600);21MODULE_PARM_DESC(time_secs, "lockup time in seconds, default 0");22 23static unsigned int time_nsecs;24module_param(time_nsecs, uint, 0600);25MODULE_PARM_DESC(time_nsecs, "nanoseconds part of lockup time, default 0");26 27static unsigned int cooldown_secs;28module_param(cooldown_secs, uint, 0600);29MODULE_PARM_DESC(cooldown_secs, "cooldown time between iterations in seconds, default 0");30 31static unsigned int cooldown_nsecs;32module_param(cooldown_nsecs, uint, 0600);33MODULE_PARM_DESC(cooldown_nsecs, "nanoseconds part of cooldown, default 0");34 35static unsigned int iterations = 1;36module_param(iterations, uint, 0600);37MODULE_PARM_DESC(iterations, "lockup iterations, default 1");38 39static bool all_cpus;40module_param(all_cpus, bool, 0400);41MODULE_PARM_DESC(all_cpus, "trigger lockup at all cpus at once");42 43static int wait_state;44static char *state = "R";45module_param(state, charp, 0400);46MODULE_PARM_DESC(state, "wait in 'R' running (default), 'D' uninterruptible, 'K' killable, 'S' interruptible state");47 48static bool use_hrtimer;49module_param(use_hrtimer, bool, 0400);50MODULE_PARM_DESC(use_hrtimer, "use high-resolution timer for sleeping");51 52static bool iowait;53module_param(iowait, bool, 0400);54MODULE_PARM_DESC(iowait, "account sleep time as iowait");55 56static bool lock_read;57module_param(lock_read, bool, 0400);58MODULE_PARM_DESC(lock_read, "lock read-write locks for read");59 60static bool lock_single;61module_param(lock_single, bool, 0400);62MODULE_PARM_DESC(lock_single, "acquire locks only at one cpu");63 64static bool reacquire_locks;65module_param(reacquire_locks, bool, 0400);66MODULE_PARM_DESC(reacquire_locks, "release and reacquire locks/irq/preempt between iterations");67 68static bool touch_softlockup;69module_param(touch_softlockup, bool, 0600);70MODULE_PARM_DESC(touch_softlockup, "touch soft-lockup watchdog between iterations");71 72static bool touch_hardlockup;73module_param(touch_hardlockup, bool, 0600);74MODULE_PARM_DESC(touch_hardlockup, "touch hard-lockup watchdog between iterations");75 76static bool call_cond_resched;77module_param(call_cond_resched, bool, 0600);78MODULE_PARM_DESC(call_cond_resched, "call cond_resched() between iterations");79 80static bool measure_lock_wait;81module_param(measure_lock_wait, bool, 0400);82MODULE_PARM_DESC(measure_lock_wait, "measure lock wait time");83 84static unsigned long lock_wait_threshold = ULONG_MAX;85module_param(lock_wait_threshold, ulong, 0400);86MODULE_PARM_DESC(lock_wait_threshold, "print lock wait time longer than this in nanoseconds, default off");87 88static bool test_disable_irq;89module_param_named(disable_irq, test_disable_irq, bool, 0400);90MODULE_PARM_DESC(disable_irq, "disable interrupts: generate hard-lockups");91 92static bool disable_softirq;93module_param(disable_softirq, bool, 0400);94MODULE_PARM_DESC(disable_softirq, "disable bottom-half irq handlers");95 96static bool disable_preempt;97module_param(disable_preempt, bool, 0400);98MODULE_PARM_DESC(disable_preempt, "disable preemption: generate soft-lockups");99 100static bool lock_rcu;101module_param(lock_rcu, bool, 0400);102MODULE_PARM_DESC(lock_rcu, "grab rcu_read_lock: generate rcu stalls");103 104static bool lock_mmap_sem;105module_param(lock_mmap_sem, bool, 0400);106MODULE_PARM_DESC(lock_mmap_sem, "lock mm->mmap_lock: block procfs interfaces");107 108static unsigned long lock_rwsem_ptr;109module_param_unsafe(lock_rwsem_ptr, ulong, 0400);110MODULE_PARM_DESC(lock_rwsem_ptr, "lock rw_semaphore at address");111 112static unsigned long lock_mutex_ptr;113module_param_unsafe(lock_mutex_ptr, ulong, 0400);114MODULE_PARM_DESC(lock_mutex_ptr, "lock mutex at address");115 116static unsigned long lock_spinlock_ptr;117module_param_unsafe(lock_spinlock_ptr, ulong, 0400);118MODULE_PARM_DESC(lock_spinlock_ptr, "lock spinlock at address");119 120static unsigned long lock_rwlock_ptr;121module_param_unsafe(lock_rwlock_ptr, ulong, 0400);122MODULE_PARM_DESC(lock_rwlock_ptr, "lock rwlock at address");123 124static unsigned int alloc_pages_nr;125module_param_unsafe(alloc_pages_nr, uint, 0600);126MODULE_PARM_DESC(alloc_pages_nr, "allocate and free pages under locks");127 128static unsigned int alloc_pages_order;129module_param(alloc_pages_order, uint, 0400);130MODULE_PARM_DESC(alloc_pages_order, "page order to allocate");131 132static gfp_t alloc_pages_gfp = GFP_KERNEL;133module_param_unsafe(alloc_pages_gfp, uint, 0400);134MODULE_PARM_DESC(alloc_pages_gfp, "allocate pages with this gfp_mask, default GFP_KERNEL");135 136static bool alloc_pages_atomic;137module_param(alloc_pages_atomic, bool, 0400);138MODULE_PARM_DESC(alloc_pages_atomic, "allocate pages with GFP_ATOMIC");139 140static bool reallocate_pages;141module_param(reallocate_pages, bool, 0400);142MODULE_PARM_DESC(reallocate_pages, "free and allocate pages between iterations");143 144struct file *test_file;145static struct inode *test_inode;146static char test_file_path[256];147module_param_string(file_path, test_file_path, sizeof(test_file_path), 0400);148MODULE_PARM_DESC(file_path, "file path to test");149 150static bool test_lock_inode;151module_param_named(lock_inode, test_lock_inode, bool, 0400);152MODULE_PARM_DESC(lock_inode, "lock file -> inode -> i_rwsem");153 154static bool test_lock_mapping;155module_param_named(lock_mapping, test_lock_mapping, bool, 0400);156MODULE_PARM_DESC(lock_mapping, "lock file -> mapping -> i_mmap_rwsem");157 158static bool test_lock_sb_umount;159module_param_named(lock_sb_umount, test_lock_sb_umount, bool, 0400);160MODULE_PARM_DESC(lock_sb_umount, "lock file -> sb -> s_umount");161 162static atomic_t alloc_pages_failed = ATOMIC_INIT(0);163 164static atomic64_t max_lock_wait = ATOMIC64_INIT(0);165 166static struct task_struct *main_task;167static int master_cpu;168 169static void test_lock(bool master, bool verbose)170{171 u64 wait_start;172 173 if (measure_lock_wait)174 wait_start = local_clock();175 176 if (lock_mutex_ptr && master) {177 if (verbose)178 pr_notice("lock mutex %ps\n", (void *)lock_mutex_ptr);179 mutex_lock((struct mutex *)lock_mutex_ptr);180 }181 182 if (lock_rwsem_ptr && master) {183 if (verbose)184 pr_notice("lock rw_semaphore %ps\n",185 (void *)lock_rwsem_ptr);186 if (lock_read)187 down_read((struct rw_semaphore *)lock_rwsem_ptr);188 else189 down_write((struct rw_semaphore *)lock_rwsem_ptr);190 }191 192 if (lock_mmap_sem && master) {193 if (verbose)194 pr_notice("lock mmap_lock pid=%d\n", main_task->pid);195 if (lock_read)196 mmap_read_lock(main_task->mm);197 else198 mmap_write_lock(main_task->mm);199 }200 201 if (test_disable_irq)202 local_irq_disable();203 204 if (disable_softirq)205 local_bh_disable();206 207 if (disable_preempt)208 preempt_disable();209 210 if (lock_rcu)211 rcu_read_lock();212 213 if (lock_spinlock_ptr && master) {214 if (verbose)215 pr_notice("lock spinlock %ps\n",216 (void *)lock_spinlock_ptr);217 spin_lock((spinlock_t *)lock_spinlock_ptr);218 }219 220 if (lock_rwlock_ptr && master) {221 if (verbose)222 pr_notice("lock rwlock %ps\n",223 (void *)lock_rwlock_ptr);224 if (lock_read)225 read_lock((rwlock_t *)lock_rwlock_ptr);226 else227 write_lock((rwlock_t *)lock_rwlock_ptr);228 }229 230 if (measure_lock_wait) {231 s64 cur_wait = local_clock() - wait_start;232 s64 max_wait = atomic64_read(&max_lock_wait);233 234 do {235 if (cur_wait < max_wait)236 break;237 max_wait = atomic64_cmpxchg(&max_lock_wait,238 max_wait, cur_wait);239 } while (max_wait != cur_wait);240 241 if (cur_wait > lock_wait_threshold)242 pr_notice_ratelimited("lock wait %lld ns\n", cur_wait);243 }244}245 246static void test_unlock(bool master, bool verbose)247{248 if (lock_rwlock_ptr && master) {249 if (lock_read)250 read_unlock((rwlock_t *)lock_rwlock_ptr);251 else252 write_unlock((rwlock_t *)lock_rwlock_ptr);253 if (verbose)254 pr_notice("unlock rwlock %ps\n",255 (void *)lock_rwlock_ptr);256 }257 258 if (lock_spinlock_ptr && master) {259 spin_unlock((spinlock_t *)lock_spinlock_ptr);260 if (verbose)261 pr_notice("unlock spinlock %ps\n",262 (void *)lock_spinlock_ptr);263 }264 265 if (lock_rcu)266 rcu_read_unlock();267 268 if (disable_preempt)269 preempt_enable();270 271 if (disable_softirq)272 local_bh_enable();273 274 if (test_disable_irq)275 local_irq_enable();276 277 if (lock_mmap_sem && master) {278 if (lock_read)279 mmap_read_unlock(main_task->mm);280 else281 mmap_write_unlock(main_task->mm);282 if (verbose)283 pr_notice("unlock mmap_lock pid=%d\n", main_task->pid);284 }285 286 if (lock_rwsem_ptr && master) {287 if (lock_read)288 up_read((struct rw_semaphore *)lock_rwsem_ptr);289 else290 up_write((struct rw_semaphore *)lock_rwsem_ptr);291 if (verbose)292 pr_notice("unlock rw_semaphore %ps\n",293 (void *)lock_rwsem_ptr);294 }295 296 if (lock_mutex_ptr && master) {297 mutex_unlock((struct mutex *)lock_mutex_ptr);298 if (verbose)299 pr_notice("unlock mutex %ps\n",300 (void *)lock_mutex_ptr);301 }302}303 304static void test_alloc_pages(struct list_head *pages)305{306 struct page *page;307 unsigned int i;308 309 for (i = 0; i < alloc_pages_nr; i++) {310 page = alloc_pages(alloc_pages_gfp, alloc_pages_order);311 if (!page) {312 atomic_inc(&alloc_pages_failed);313 break;314 }315 list_add(&page->lru, pages);316 }317}318 319static void test_free_pages(struct list_head *pages)320{321 struct page *page, *next;322 323 list_for_each_entry_safe(page, next, pages, lru)324 __free_pages(page, alloc_pages_order);325 INIT_LIST_HEAD(pages);326}327 328static void test_wait(unsigned int secs, unsigned int nsecs)329{330 if (wait_state == TASK_RUNNING) {331 if (secs)332 mdelay(secs * MSEC_PER_SEC);333 if (nsecs)334 ndelay(nsecs);335 return;336 }337 338 __set_current_state(wait_state);339 if (use_hrtimer) {340 ktime_t time;341 342 time = ns_to_ktime((u64)secs * NSEC_PER_SEC + nsecs);343 schedule_hrtimeout(&time, HRTIMER_MODE_REL);344 } else {345 schedule_timeout(secs * HZ + nsecs_to_jiffies(nsecs));346 }347}348 349static void test_lockup(bool master)350{351 u64 lockup_start = local_clock();352 unsigned int iter = 0;353 LIST_HEAD(pages);354 355 pr_notice("Start on CPU%d\n", raw_smp_processor_id());356 357 test_lock(master, true);358 359 test_alloc_pages(&pages);360 361 while (iter++ < iterations && !signal_pending(main_task)) {362 363 if (iowait)364 current->in_iowait = 1;365 366 test_wait(time_secs, time_nsecs);367 368 if (iowait)369 current->in_iowait = 0;370 371 if (reallocate_pages)372 test_free_pages(&pages);373 374 if (reacquire_locks)375 test_unlock(master, false);376 377 if (touch_softlockup)378 touch_softlockup_watchdog();379 380 if (touch_hardlockup)381 touch_nmi_watchdog();382 383 if (call_cond_resched)384 cond_resched();385 386 test_wait(cooldown_secs, cooldown_nsecs);387 388 if (reacquire_locks)389 test_lock(master, false);390 391 if (reallocate_pages)392 test_alloc_pages(&pages);393 }394 395 pr_notice("Finish on CPU%d in %lld ns\n", raw_smp_processor_id(),396 local_clock() - lockup_start);397 398 test_free_pages(&pages);399 400 test_unlock(master, true);401}402 403static DEFINE_PER_CPU(struct work_struct, test_works);404 405static void test_work_fn(struct work_struct *work)406{407 test_lockup(!lock_single ||408 work == per_cpu_ptr(&test_works, master_cpu));409}410 411static bool test_kernel_ptr(unsigned long addr, int size)412{413 void *ptr = (void *)addr;414 char buf;415 416 if (!addr)417 return false;418 419 /* should be at least readable kernel address */420 if (!IS_ENABLED(CONFIG_ALTERNATE_USER_ADDRESS_SPACE) &&421 (access_ok((void __user *)ptr, 1) ||422 access_ok((void __user *)ptr + size - 1, 1))) {423 pr_err("user space ptr invalid in kernel: %#lx\n", addr);424 return true;425 }426 427 if (get_kernel_nofault(buf, ptr) ||428 get_kernel_nofault(buf, ptr + size - 1)) {429 pr_err("invalid kernel ptr: %#lx\n", addr);430 return true;431 }432 433 return false;434}435 436static bool __maybe_unused test_magic(unsigned long addr, int offset,437 unsigned int expected)438{439 void *ptr = (void *)addr + offset;440 unsigned int magic = 0;441 442 if (!addr)443 return false;444 445 if (get_kernel_nofault(magic, ptr) || magic != expected) {446 pr_err("invalid magic at %#lx + %#x = %#x, expected %#x\n",447 addr, offset, magic, expected);448 return true;449 }450 451 return false;452}453 454static int __init test_lockup_init(void)455{456 u64 test_start = local_clock();457 458 main_task = current;459 460 switch (state[0]) {461 case 'S':462 wait_state = TASK_INTERRUPTIBLE;463 break;464 case 'D':465 wait_state = TASK_UNINTERRUPTIBLE;466 break;467 case 'K':468 wait_state = TASK_KILLABLE;469 break;470 case 'R':471 wait_state = TASK_RUNNING;472 break;473 default:474 pr_err("unknown state=%s\n", state);475 return -EINVAL;476 }477 478 if (alloc_pages_atomic)479 alloc_pages_gfp = GFP_ATOMIC;480 481 if (test_kernel_ptr(lock_spinlock_ptr, sizeof(spinlock_t)) ||482 test_kernel_ptr(lock_rwlock_ptr, sizeof(rwlock_t)) ||483 test_kernel_ptr(lock_mutex_ptr, sizeof(struct mutex)) ||484 test_kernel_ptr(lock_rwsem_ptr, sizeof(struct rw_semaphore)))485 return -EINVAL;486 487#ifdef CONFIG_DEBUG_SPINLOCK488#ifdef CONFIG_PREEMPT_RT489 if (test_magic(lock_spinlock_ptr,490 offsetof(spinlock_t, lock.wait_lock.magic),491 SPINLOCK_MAGIC) ||492 test_magic(lock_rwlock_ptr,493 offsetof(rwlock_t, rwbase.rtmutex.wait_lock.magic),494 SPINLOCK_MAGIC) ||495 test_magic(lock_mutex_ptr,496 offsetof(struct mutex, rtmutex.wait_lock.magic),497 SPINLOCK_MAGIC) ||498 test_magic(lock_rwsem_ptr,499 offsetof(struct rw_semaphore, rwbase.rtmutex.wait_lock.magic),500 SPINLOCK_MAGIC))501 return -EINVAL;502#else503 if (test_magic(lock_spinlock_ptr,504 offsetof(spinlock_t, rlock.magic),505 SPINLOCK_MAGIC) ||506 test_magic(lock_rwlock_ptr,507 offsetof(rwlock_t, magic),508 RWLOCK_MAGIC) ||509 test_magic(lock_mutex_ptr,510 offsetof(struct mutex, wait_lock.magic),511 SPINLOCK_MAGIC) ||512 test_magic(lock_rwsem_ptr,513 offsetof(struct rw_semaphore, wait_lock.magic),514 SPINLOCK_MAGIC))515 return -EINVAL;516#endif517#endif518 519 if ((wait_state != TASK_RUNNING ||520 (call_cond_resched && !reacquire_locks) ||521 (alloc_pages_nr && gfpflags_allow_blocking(alloc_pages_gfp))) &&522 (test_disable_irq || disable_softirq || disable_preempt ||523 lock_rcu || lock_spinlock_ptr || lock_rwlock_ptr)) {524 pr_err("refuse to sleep in atomic context\n");525 return -EINVAL;526 }527 528 if (lock_mmap_sem && !main_task->mm) {529 pr_err("no mm to lock mmap_lock\n");530 return -EINVAL;531 }532 533 if (test_file_path[0]) {534 test_file = filp_open(test_file_path, O_RDONLY, 0);535 if (IS_ERR(test_file)) {536 pr_err("failed to open %s: %ld\n", test_file_path, PTR_ERR(test_file));537 return PTR_ERR(test_file);538 }539 test_inode = file_inode(test_file);540 } else if (test_lock_inode ||541 test_lock_mapping ||542 test_lock_sb_umount) {543 pr_err("no file to lock\n");544 return -EINVAL;545 }546 547 if (test_lock_inode && test_inode)548 lock_rwsem_ptr = (unsigned long)&test_inode->i_rwsem;549 550 if (test_lock_mapping && test_file && test_file->f_mapping)551 lock_rwsem_ptr = (unsigned long)&test_file->f_mapping->i_mmap_rwsem;552 553 if (test_lock_sb_umount && test_inode)554 lock_rwsem_ptr = (unsigned long)&test_inode->i_sb->s_umount;555 556 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",557 main_task->pid, time_secs, time_nsecs,558 cooldown_secs, cooldown_nsecs, iterations, state,559 all_cpus ? "all_cpus " : "",560 iowait ? "iowait " : "",561 test_disable_irq ? "disable_irq " : "",562 disable_softirq ? "disable_softirq " : "",563 disable_preempt ? "disable_preempt " : "",564 lock_rcu ? "lock_rcu " : "",565 lock_read ? "lock_read " : "",566 touch_softlockup ? "touch_softlockup " : "",567 touch_hardlockup ? "touch_hardlockup " : "",568 call_cond_resched ? "call_cond_resched " : "",569 reacquire_locks ? "reacquire_locks " : "");570 571 if (alloc_pages_nr)572 pr_notice("ALLOCATE PAGES nr=%u order=%u gfp=%pGg %s\n",573 alloc_pages_nr, alloc_pages_order, &alloc_pages_gfp,574 reallocate_pages ? "reallocate_pages " : "");575 576 if (all_cpus) {577 unsigned int cpu;578 579 cpus_read_lock();580 581 preempt_disable();582 master_cpu = smp_processor_id();583 for_each_online_cpu(cpu) {584 INIT_WORK(per_cpu_ptr(&test_works, cpu), test_work_fn);585 queue_work_on(cpu, system_highpri_wq,586 per_cpu_ptr(&test_works, cpu));587 }588 preempt_enable();589 590 for_each_online_cpu(cpu)591 flush_work(per_cpu_ptr(&test_works, cpu));592 593 cpus_read_unlock();594 } else {595 test_lockup(true);596 }597 598 if (measure_lock_wait)599 pr_notice("Maximum lock wait: %lld ns\n",600 atomic64_read(&max_lock_wait));601 602 if (alloc_pages_nr)603 pr_notice("Page allocation failed %u times\n",604 atomic_read(&alloc_pages_failed));605 606 pr_notice("FINISH in %llu ns\n", local_clock() - test_start);607 608 if (test_file)609 fput(test_file);610 611 if (signal_pending(main_task))612 return -EINTR;613 614 return -EAGAIN;615}616module_init(test_lockup_init);617 618MODULE_LICENSE("GPL");619MODULE_AUTHOR("Konstantin Khlebnikov <khlebnikov@yandex-team.ru>");620MODULE_DESCRIPTION("Test module to generate lockups");621