/* * Module-based torture test facility for locking * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, you can access it online at * http://www.gnu.org/licenses/gpl-2.0.html. * * Copyright (C) IBM Corporation, 2014 * * Author: Paul E. McKenney * Based on kernel/rcu/torture.c. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include MODULE_LICENSE("GPL"); MODULE_AUTHOR("Paul E. McKenney "); torture_param(int, nwriters_stress, -1, "Number of write-locking stress-test threads"); torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)"); torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (s), 0=disable"); torture_param(int, shuffle_interval, 3, "Number of jiffies between shuffles, 0=disable"); torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable."); torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s"); torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable"); torture_param(bool, verbose, true, "Enable verbose debugging printk()s"); static bool debug_lock = false; static char *torture_type = "spin_lock"; module_param(torture_type, charp, 0444); MODULE_PARM_DESC(torture_type, "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)"); static atomic_t n_lock_torture_errors; static struct task_struct *stats_task; static struct task_struct **writer_tasks; static int nrealwriters_stress; static bool lock_is_write_held; struct lock_stress_stats { long n_lock_fail; long n_lock_acquired; }; static struct lock_stress_stats *lwsa; /* writer statistics */ #if defined(MODULE) #define LOCKTORTURE_RUNNABLE_INIT 1 #else #define LOCKTORTURE_RUNNABLE_INIT 0 #endif int torture_runnable = LOCKTORTURE_RUNNABLE_INIT; module_param(torture_runnable, int, 0444); MODULE_PARM_DESC(torture_runnable, "Start locktorture at module init"); /* Forward reference. */ static void lock_torture_cleanup(void); /* * Operations vector for selecting different types of tests. */ struct lock_torture_ops { void (*init)(void); int (*writelock)(void); void (*write_delay)(struct torture_random_state *trsp); void (*writeunlock)(void); unsigned long flags; const char *name; }; static struct lock_torture_ops *cur_ops; /* * Definitions for lock torture testing. */ static int torture_lock_busted_write_lock(void) { return 0; /* BUGGY, do not use in real life!!! */ } static void torture_lock_busted_write_delay(struct torture_random_state *trsp) { const unsigned long longdelay_us = 100; /* We want a long delay occasionally to force massive contention. */ if (!(torture_random(trsp) % (nrealwriters_stress * 2000 * longdelay_us))) mdelay(longdelay_us); #ifdef CONFIG_PREEMPT if (!(torture_random(trsp) % (nrealwriters_stress * 20000))) preempt_schedule(); /* Allow test to be preempted. */ #endif } static void torture_lock_busted_write_unlock(void) { /* BUGGY, do not use in real life!!! */ } static struct lock_torture_ops lock_busted_ops = { .writelock = torture_lock_busted_write_lock, .write_delay = torture_lock_busted_write_delay, .writeunlock = torture_lock_busted_write_unlock, .name = "lock_busted" }; static DEFINE_SPINLOCK(torture_spinlock); static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock) { spin_lock(&torture_spinlock); return 0; } static void torture_spin_lock_write_delay(struct torture_random_state *trsp) { const unsigned long shortdelay_us = 2; const unsigned long longdelay_us = 100; /* We want a short delay mostly to emulate likely code, and * we want a long delay occasionally to force massive contention. */ if (!(torture_random(trsp) % (nrealwriters_stress * 2000 * longdelay_us))) mdelay(longdelay_us); if (!(torture_random(trsp) % (nrealwriters_stress * 2 * shortdelay_us))) udelay(shortdelay_us); #ifdef CONFIG_PREEMPT if (!(torture_random(trsp) % (nrealwriters_stress * 20000))) preempt_schedule(); /* Allow test to be preempted. */ #endif } static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock) { spin_unlock(&torture_spinlock); } static struct lock_torture_ops spin_lock_ops = { .writelock = torture_spin_lock_write_lock, .write_delay = torture_spin_lock_write_delay, .writeunlock = torture_spin_lock_write_unlock, .name = "spin_lock" }; static int torture_spin_lock_write_lock_irq(void) __acquires(torture_spinlock_irq) { unsigned long flags; spin_lock_irqsave(&torture_spinlock, flags); cur_ops->flags = flags; return 0; } static void torture_lock_spin_write_unlock_irq(void) __releases(torture_spinlock) { spin_unlock_irqrestore(&torture_spinlock, cur_ops->flags); } static struct lock_torture_ops spin_lock_irq_ops = { .writelock = torture_spin_lock_write_lock_irq, .write_delay = torture_spin_lock_write_delay, .writeunlock = torture_lock_spin_write_unlock_irq, .name = "spin_lock_irq" }; static DEFINE_MUTEX(torture_mutex); static int torture_mutex_lock(void) __acquires(torture_mutex) { mutex_lock(&torture_mutex); return 0; } static void torture_mutex_delay(struct torture_random_state *trsp) { const unsigned long longdelay_ms = 100; /* We want a long delay occasionally to force massive contention. */ if (!(torture_random(trsp) % (nrealwriters_stress * 2000 * longdelay_ms))) mdelay(longdelay_ms * 5); else mdelay(longdelay_ms / 5); #ifdef CONFIG_PREEMPT if (!(torture_random(trsp) % (nrealwriters_stress * 20000))) preempt_schedule(); /* Allow test to be preempted. */ #endif } static void torture_mutex_unlock(void) __releases(torture_mutex) { mutex_unlock(&torture_mutex); } static struct lock_torture_ops mutex_lock_ops = { .writelock = torture_mutex_lock, .write_delay = torture_mutex_delay, .writeunlock = torture_mutex_unlock, .name = "mutex_lock" }; /* * Lock torture writer kthread. Repeatedly acquires and releases * the lock, checking for duplicate acquisitions. */ static int lock_torture_writer(void *arg) { struct lock_stress_stats *lwsp = arg; static DEFINE_TORTURE_RANDOM(rand); VERBOSE_TOROUT_STRING("lock_torture_writer task started"); set_user_nice(current, MAX_NICE); do { if ((torture_random(&rand) & 0xfffff) == 0) schedule_timeout_uninterruptible(1); cur_ops->writelock(); if (WARN_ON_ONCE(lock_is_write_held)) lwsp->n_lock_fail++; lock_is_write_held = 1; lwsp->n_lock_acquired++; cur_ops->write_delay(&rand); lock_is_write_held = 0; cur_ops->writeunlock(); stutter_wait("lock_torture_writer"); } while (!torture_must_stop()); torture_kthread_stopping("lock_torture_writer"); return 0; } /* * Create an lock-torture-statistics message in the specified buffer. */ static void lock_torture_printk(char *page) { bool fail = 0; int i; long max = 0; long min = lwsa[0].n_lock_acquired; long long sum = 0; for (i = 0; i < nrealwriters_stress; i++) { if (lwsa[i].n_lock_fail) fail = true; sum += lwsa[i].n_lock_acquired; if (max < lwsa[i].n_lock_fail) max = lwsa[i].n_lock_fail; if (min > lwsa[i].n_lock_fail) min = lwsa[i].n_lock_fail; } page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG); page += sprintf(page, "Writes: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n", sum, max, min, max / 2 > min ? "???" : "", fail, fail ? "!!!" : ""); if (fail) atomic_inc(&n_lock_torture_errors); } /* * Print torture statistics. Caller must ensure that there is only one * call to this function at a given time!!! This is normally accomplished * by relying on the module system to only have one copy of the module * loaded, and then by giving the lock_torture_stats kthread full control * (or the init/cleanup functions when lock_torture_stats thread is not * running). */ static void lock_torture_stats_print(void) { int size = nrealwriters_stress * 200 + 8192; char *buf; buf = kmalloc(size, GFP_KERNEL); if (!buf) { pr_err("lock_torture_stats_print: Out of memory, need: %d", size); return; } lock_torture_printk(buf); pr_alert("%s", buf); kfree(buf); } /* * Periodically prints torture statistics, if periodic statistics printing * was specified via the stat_interval module parameter. * * No need to worry about fullstop here, since this one doesn't reference * volatile state or register callbacks. */ static int lock_torture_stats(void *arg) { VERBOSE_TOROUT_STRING("lock_torture_stats task started"); do { schedule_timeout_interruptible(stat_interval * HZ); lock_torture_stats_print(); torture_shutdown_absorb("lock_torture_stats"); } while (!torture_must_stop()); torture_kthread_stopping("lock_torture_stats"); return 0; } static inline void lock_torture_print_module_parms(struct lock_torture_ops *cur_ops, const char *tag) { pr_alert("%s" TORTURE_FLAG "--- %s%s: nwriters_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n", torture_type, tag, debug_lock ? " [debug]": "", nrealwriters_stress, stat_interval, verbose, shuffle_interval, stutter, shutdown_secs, onoff_interval, onoff_holdoff); } static void lock_torture_cleanup(void) { int i; if (torture_cleanup()) return; if (writer_tasks) { for (i = 0; i < nrealwriters_stress; i++) torture_stop_kthread(lock_torture_writer, writer_tasks[i]); kfree(writer_tasks); writer_tasks = NULL; } torture_stop_kthread(lock_torture_stats, stats_task); lock_torture_stats_print(); /* -After- the stats thread is stopped! */ if (atomic_read(&n_lock_torture_errors)) lock_torture_print_module_parms(cur_ops, "End of test: FAILURE"); else if (torture_onoff_failures()) lock_torture_print_module_parms(cur_ops, "End of test: LOCK_HOTPLUG"); else lock_torture_print_module_parms(cur_ops, "End of test: SUCCESS"); } static int __init lock_torture_init(void) { int i; int firsterr = 0; static struct lock_torture_ops *torture_ops[] = { &lock_busted_ops, &spin_lock_ops, &spin_lock_irq_ops, &mutex_lock_ops, }; if (!torture_init_begin(torture_type, verbose, &torture_runnable)) return -EBUSY; /* Process args and tell the world that the torturer is on the job. */ for (i = 0; i < ARRAY_SIZE(torture_ops); i++) { cur_ops = torture_ops[i]; if (strcmp(torture_type, cur_ops->name) == 0) break; } if (i == ARRAY_SIZE(torture_ops)) { pr_alert("lock-torture: invalid torture type: \"%s\"\n", torture_type); pr_alert("lock-torture types:"); for (i = 0; i < ARRAY_SIZE(torture_ops); i++) pr_alert(" %s", torture_ops[i]->name); pr_alert("\n"); torture_init_end(); return -EINVAL; } if (cur_ops->init) cur_ops->init(); /* no "goto unwind" prior to this point!!! */ if (nwriters_stress >= 0) nrealwriters_stress = nwriters_stress; else nrealwriters_stress = 2 * num_online_cpus(); #ifdef CONFIG_DEBUG_MUTEXES if (strncmp(torture_type, "mutex", 5) == 0) debug_lock = true; #endif #ifdef CONFIG_DEBUG_SPINLOCK if (strncmp(torture_type, "spin", 4) == 0) debug_lock = true; #endif lock_torture_print_module_parms(cur_ops, "Start of test"); /* Initialize the statistics so that each run gets its own numbers. */ lock_is_write_held = 0; lwsa = kmalloc(sizeof(*lwsa) * nrealwriters_stress, GFP_KERNEL); if (lwsa == NULL) { VERBOSE_TOROUT_STRING("lwsa: Out of memory"); firsterr = -ENOMEM; goto unwind; } for (i = 0; i < nrealwriters_stress; i++) { lwsa[i].n_lock_fail = 0; lwsa[i].n_lock_acquired = 0; } /* Start up the kthreads. */ if (onoff_interval > 0) { firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval * HZ); if (firsterr) goto unwind; } if (shuffle_interval > 0) { firsterr = torture_shuffle_init(shuffle_interval); if (firsterr) goto unwind; } if (shutdown_secs > 0) { firsterr = torture_shutdown_init(shutdown_secs, lock_torture_cleanup); if (firsterr) goto unwind; } if (stutter > 0) { firsterr = torture_stutter_init(stutter); if (firsterr) goto unwind; } writer_tasks = kzalloc(nrealwriters_stress * sizeof(writer_tasks[0]), GFP_KERNEL); if (writer_tasks == NULL) { VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory"); firsterr = -ENOMEM; goto unwind; } for (i = 0; i < nrealwriters_stress; i++) { firsterr = torture_create_kthread(lock_torture_writer, &lwsa[i], writer_tasks[i]); if (firsterr) goto unwind; } if (stat_interval > 0) { firsterr = torture_create_kthread(lock_torture_stats, NULL, stats_task); if (firsterr) goto unwind; } torture_init_end(); return 0; unwind: torture_init_end(); lock_torture_cleanup(); return firsterr; } module_init(lock_torture_init); module_exit(lock_torture_cleanup);