v4.19.13 snapshot.
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
new file mode 100644
index 0000000..7d0b0ed
--- /dev/null
+++ b/kernel/locking/locktorture.c
@@ -0,0 +1,1062 @@
+/*
+ * 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
+ *
+ * Authors: Paul E. McKenney <paulmck@us.ibm.com>
+ * Davidlohr Bueso <dave@stgolabs.net>
+ * Based on kernel/rcu/torture.c.
+ */
+
+#define pr_fmt(fmt) fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/sched/rt.h>
+#include <linux/spinlock.h>
+#include <linux/rwlock.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <uapi/linux/sched/types.h>
+#include <linux/rtmutex.h>
+#include <linux/atomic.h>
+#include <linux/moduleparam.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/percpu-rwsem.h>
+#include <linux/torture.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
+
+torture_param(int, nwriters_stress, -1,
+ "Number of write-locking stress-test threads");
+torture_param(int, nreaders_stress, -1,
+ "Number of read-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(int, verbose, 1,
+ "Enable verbose debugging printk()s");
+
+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 struct task_struct *stats_task;
+static struct task_struct **writer_tasks;
+static struct task_struct **reader_tasks;
+
+static bool lock_is_write_held;
+static bool lock_is_read_held;
+
+struct lock_stress_stats {
+ long n_lock_fail;
+ long n_lock_acquired;
+};
+
+/* 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 (*task_boost)(struct torture_random_state *trsp);
+ void (*writeunlock)(void);
+ int (*readlock)(void);
+ void (*read_delay)(struct torture_random_state *trsp);
+ void (*readunlock)(void);
+
+ unsigned long flags; /* for irq spinlocks */
+ const char *name;
+};
+
+struct lock_torture_cxt {
+ int nrealwriters_stress;
+ int nrealreaders_stress;
+ bool debug_lock;
+ atomic_t n_lock_torture_errors;
+ struct lock_torture_ops *cur_ops;
+ struct lock_stress_stats *lwsa; /* writer statistics */
+ struct lock_stress_stats *lrsa; /* reader statistics */
+};
+static struct lock_torture_cxt cxt = { 0, 0, false,
+ ATOMIC_INIT(0),
+ NULL, NULL};
+/*
+ * 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_ms = 100;
+
+ /* We want a long delay occasionally to force massive contention. */
+ if (!(torture_random(trsp) %
+ (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
+ mdelay(longdelay_ms);
+ if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
+ torture_preempt_schedule(); /* Allow test to be preempted. */
+}
+
+static void torture_lock_busted_write_unlock(void)
+{
+ /* BUGGY, do not use in real life!!! */
+}
+
+static void torture_boost_dummy(struct torture_random_state *trsp)
+{
+ /* Only rtmutexes care about priority */
+}
+
+static struct lock_torture_ops lock_busted_ops = {
+ .writelock = torture_lock_busted_write_lock,
+ .write_delay = torture_lock_busted_write_delay,
+ .task_boost = torture_boost_dummy,
+ .writeunlock = torture_lock_busted_write_unlock,
+ .readlock = NULL,
+ .read_delay = NULL,
+ .readunlock = NULL,
+ .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_ms = 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) %
+ (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
+ mdelay(longdelay_ms);
+ if (!(torture_random(trsp) %
+ (cxt.nrealwriters_stress * 2 * shortdelay_us)))
+ udelay(shortdelay_us);
+ if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
+ torture_preempt_schedule(); /* Allow test to be preempted. */
+}
+
+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,
+ .task_boost = torture_boost_dummy,
+ .writeunlock = torture_spin_lock_write_unlock,
+ .readlock = NULL,
+ .read_delay = NULL,
+ .readunlock = NULL,
+ .name = "spin_lock"
+};
+
+static int torture_spin_lock_write_lock_irq(void)
+__acquires(torture_spinlock)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&torture_spinlock, flags);
+ cxt.cur_ops->flags = flags;
+ return 0;
+}
+
+static void torture_lock_spin_write_unlock_irq(void)
+__releases(torture_spinlock)
+{
+ spin_unlock_irqrestore(&torture_spinlock, cxt.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,
+ .task_boost = torture_boost_dummy,
+ .writeunlock = torture_lock_spin_write_unlock_irq,
+ .readlock = NULL,
+ .read_delay = NULL,
+ .readunlock = NULL,
+ .name = "spin_lock_irq"
+};
+
+static DEFINE_RWLOCK(torture_rwlock);
+
+static int torture_rwlock_write_lock(void) __acquires(torture_rwlock)
+{
+ write_lock(&torture_rwlock);
+ return 0;
+}
+
+static void torture_rwlock_write_delay(struct torture_random_state *trsp)
+{
+ const unsigned long shortdelay_us = 2;
+ const unsigned long longdelay_ms = 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) %
+ (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
+ mdelay(longdelay_ms);
+ else
+ udelay(shortdelay_us);
+}
+
+static void torture_rwlock_write_unlock(void) __releases(torture_rwlock)
+{
+ write_unlock(&torture_rwlock);
+}
+
+static int torture_rwlock_read_lock(void) __acquires(torture_rwlock)
+{
+ read_lock(&torture_rwlock);
+ return 0;
+}
+
+static void torture_rwlock_read_delay(struct torture_random_state *trsp)
+{
+ const unsigned long shortdelay_us = 10;
+ const unsigned long longdelay_ms = 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) %
+ (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
+ mdelay(longdelay_ms);
+ else
+ udelay(shortdelay_us);
+}
+
+static void torture_rwlock_read_unlock(void) __releases(torture_rwlock)
+{
+ read_unlock(&torture_rwlock);
+}
+
+static struct lock_torture_ops rw_lock_ops = {
+ .writelock = torture_rwlock_write_lock,
+ .write_delay = torture_rwlock_write_delay,
+ .task_boost = torture_boost_dummy,
+ .writeunlock = torture_rwlock_write_unlock,
+ .readlock = torture_rwlock_read_lock,
+ .read_delay = torture_rwlock_read_delay,
+ .readunlock = torture_rwlock_read_unlock,
+ .name = "rw_lock"
+};
+
+static int torture_rwlock_write_lock_irq(void) __acquires(torture_rwlock)
+{
+ unsigned long flags;
+
+ write_lock_irqsave(&torture_rwlock, flags);
+ cxt.cur_ops->flags = flags;
+ return 0;
+}
+
+static void torture_rwlock_write_unlock_irq(void)
+__releases(torture_rwlock)
+{
+ write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
+}
+
+static int torture_rwlock_read_lock_irq(void) __acquires(torture_rwlock)
+{
+ unsigned long flags;
+
+ read_lock_irqsave(&torture_rwlock, flags);
+ cxt.cur_ops->flags = flags;
+ return 0;
+}
+
+static void torture_rwlock_read_unlock_irq(void)
+__releases(torture_rwlock)
+{
+ read_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
+}
+
+static struct lock_torture_ops rw_lock_irq_ops = {
+ .writelock = torture_rwlock_write_lock_irq,
+ .write_delay = torture_rwlock_write_delay,
+ .task_boost = torture_boost_dummy,
+ .writeunlock = torture_rwlock_write_unlock_irq,
+ .readlock = torture_rwlock_read_lock_irq,
+ .read_delay = torture_rwlock_read_delay,
+ .readunlock = torture_rwlock_read_unlock_irq,
+ .name = "rw_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) %
+ (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
+ mdelay(longdelay_ms * 5);
+ else
+ mdelay(longdelay_ms / 5);
+ if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
+ torture_preempt_schedule(); /* Allow test to be preempted. */
+}
+
+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,
+ .task_boost = torture_boost_dummy,
+ .writeunlock = torture_mutex_unlock,
+ .readlock = NULL,
+ .read_delay = NULL,
+ .readunlock = NULL,
+ .name = "mutex_lock"
+};
+
+#include <linux/ww_mutex.h>
+static DEFINE_WD_CLASS(torture_ww_class);
+static DEFINE_WW_MUTEX(torture_ww_mutex_0, &torture_ww_class);
+static DEFINE_WW_MUTEX(torture_ww_mutex_1, &torture_ww_class);
+static DEFINE_WW_MUTEX(torture_ww_mutex_2, &torture_ww_class);
+
+static int torture_ww_mutex_lock(void)
+__acquires(torture_ww_mutex_0)
+__acquires(torture_ww_mutex_1)
+__acquires(torture_ww_mutex_2)
+{
+ LIST_HEAD(list);
+ struct reorder_lock {
+ struct list_head link;
+ struct ww_mutex *lock;
+ } locks[3], *ll, *ln;
+ struct ww_acquire_ctx ctx;
+
+ locks[0].lock = &torture_ww_mutex_0;
+ list_add(&locks[0].link, &list);
+
+ locks[1].lock = &torture_ww_mutex_1;
+ list_add(&locks[1].link, &list);
+
+ locks[2].lock = &torture_ww_mutex_2;
+ list_add(&locks[2].link, &list);
+
+ ww_acquire_init(&ctx, &torture_ww_class);
+
+ list_for_each_entry(ll, &list, link) {
+ int err;
+
+ err = ww_mutex_lock(ll->lock, &ctx);
+ if (!err)
+ continue;
+
+ ln = ll;
+ list_for_each_entry_continue_reverse(ln, &list, link)
+ ww_mutex_unlock(ln->lock);
+
+ if (err != -EDEADLK)
+ return err;
+
+ ww_mutex_lock_slow(ll->lock, &ctx);
+ list_move(&ll->link, &list);
+ }
+
+ ww_acquire_fini(&ctx);
+ return 0;
+}
+
+static void torture_ww_mutex_unlock(void)
+__releases(torture_ww_mutex_0)
+__releases(torture_ww_mutex_1)
+__releases(torture_ww_mutex_2)
+{
+ ww_mutex_unlock(&torture_ww_mutex_0);
+ ww_mutex_unlock(&torture_ww_mutex_1);
+ ww_mutex_unlock(&torture_ww_mutex_2);
+}
+
+static struct lock_torture_ops ww_mutex_lock_ops = {
+ .writelock = torture_ww_mutex_lock,
+ .write_delay = torture_mutex_delay,
+ .task_boost = torture_boost_dummy,
+ .writeunlock = torture_ww_mutex_unlock,
+ .readlock = NULL,
+ .read_delay = NULL,
+ .readunlock = NULL,
+ .name = "ww_mutex_lock"
+};
+
+#ifdef CONFIG_RT_MUTEXES
+static DEFINE_RT_MUTEX(torture_rtmutex);
+
+static int torture_rtmutex_lock(void) __acquires(torture_rtmutex)
+{
+ rt_mutex_lock(&torture_rtmutex);
+ return 0;
+}
+
+static void torture_rtmutex_boost(struct torture_random_state *trsp)
+{
+ int policy;
+ struct sched_param param;
+ const unsigned int factor = 50000; /* yes, quite arbitrary */
+
+ if (!rt_task(current)) {
+ /*
+ * Boost priority once every ~50k operations. When the
+ * task tries to take the lock, the rtmutex it will account
+ * for the new priority, and do any corresponding pi-dance.
+ */
+ if (trsp && !(torture_random(trsp) %
+ (cxt.nrealwriters_stress * factor))) {
+ policy = SCHED_FIFO;
+ param.sched_priority = MAX_RT_PRIO - 1;
+ } else /* common case, do nothing */
+ return;
+ } else {
+ /*
+ * The task will remain boosted for another ~500k operations,
+ * then restored back to its original prio, and so forth.
+ *
+ * When @trsp is nil, we want to force-reset the task for
+ * stopping the kthread.
+ */
+ if (!trsp || !(torture_random(trsp) %
+ (cxt.nrealwriters_stress * factor * 2))) {
+ policy = SCHED_NORMAL;
+ param.sched_priority = 0;
+ } else /* common case, do nothing */
+ return;
+ }
+
+ sched_setscheduler_nocheck(current, policy, ¶m);
+}
+
+static void torture_rtmutex_delay(struct torture_random_state *trsp)
+{
+ const unsigned long shortdelay_us = 2;
+ const unsigned long longdelay_ms = 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) %
+ (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
+ mdelay(longdelay_ms);
+ if (!(torture_random(trsp) %
+ (cxt.nrealwriters_stress * 2 * shortdelay_us)))
+ udelay(shortdelay_us);
+ if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
+ torture_preempt_schedule(); /* Allow test to be preempted. */
+}
+
+static void torture_rtmutex_unlock(void) __releases(torture_rtmutex)
+{
+ rt_mutex_unlock(&torture_rtmutex);
+}
+
+static struct lock_torture_ops rtmutex_lock_ops = {
+ .writelock = torture_rtmutex_lock,
+ .write_delay = torture_rtmutex_delay,
+ .task_boost = torture_rtmutex_boost,
+ .writeunlock = torture_rtmutex_unlock,
+ .readlock = NULL,
+ .read_delay = NULL,
+ .readunlock = NULL,
+ .name = "rtmutex_lock"
+};
+#endif
+
+static DECLARE_RWSEM(torture_rwsem);
+static int torture_rwsem_down_write(void) __acquires(torture_rwsem)
+{
+ down_write(&torture_rwsem);
+ return 0;
+}
+
+static void torture_rwsem_write_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) %
+ (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
+ mdelay(longdelay_ms * 10);
+ else
+ mdelay(longdelay_ms / 10);
+ if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000)))
+ torture_preempt_schedule(); /* Allow test to be preempted. */
+}
+
+static void torture_rwsem_up_write(void) __releases(torture_rwsem)
+{
+ up_write(&torture_rwsem);
+}
+
+static int torture_rwsem_down_read(void) __acquires(torture_rwsem)
+{
+ down_read(&torture_rwsem);
+ return 0;
+}
+
+static void torture_rwsem_read_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) %
+ (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
+ mdelay(longdelay_ms * 2);
+ else
+ mdelay(longdelay_ms / 2);
+ if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000)))
+ torture_preempt_schedule(); /* Allow test to be preempted. */
+}
+
+static void torture_rwsem_up_read(void) __releases(torture_rwsem)
+{
+ up_read(&torture_rwsem);
+}
+
+static struct lock_torture_ops rwsem_lock_ops = {
+ .writelock = torture_rwsem_down_write,
+ .write_delay = torture_rwsem_write_delay,
+ .task_boost = torture_boost_dummy,
+ .writeunlock = torture_rwsem_up_write,
+ .readlock = torture_rwsem_down_read,
+ .read_delay = torture_rwsem_read_delay,
+ .readunlock = torture_rwsem_up_read,
+ .name = "rwsem_lock"
+};
+
+#include <linux/percpu-rwsem.h>
+static struct percpu_rw_semaphore pcpu_rwsem;
+
+void torture_percpu_rwsem_init(void)
+{
+ BUG_ON(percpu_init_rwsem(&pcpu_rwsem));
+}
+
+static int torture_percpu_rwsem_down_write(void) __acquires(pcpu_rwsem)
+{
+ percpu_down_write(&pcpu_rwsem);
+ return 0;
+}
+
+static void torture_percpu_rwsem_up_write(void) __releases(pcpu_rwsem)
+{
+ percpu_up_write(&pcpu_rwsem);
+}
+
+static int torture_percpu_rwsem_down_read(void) __acquires(pcpu_rwsem)
+{
+ percpu_down_read(&pcpu_rwsem);
+ return 0;
+}
+
+static void torture_percpu_rwsem_up_read(void) __releases(pcpu_rwsem)
+{
+ percpu_up_read(&pcpu_rwsem);
+}
+
+static struct lock_torture_ops percpu_rwsem_lock_ops = {
+ .init = torture_percpu_rwsem_init,
+ .writelock = torture_percpu_rwsem_down_write,
+ .write_delay = torture_rwsem_write_delay,
+ .task_boost = torture_boost_dummy,
+ .writeunlock = torture_percpu_rwsem_up_write,
+ .readlock = torture_percpu_rwsem_down_read,
+ .read_delay = torture_rwsem_read_delay,
+ .readunlock = torture_percpu_rwsem_up_read,
+ .name = "percpu_rwsem_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);
+
+ cxt.cur_ops->task_boost(&rand);
+ cxt.cur_ops->writelock();
+ if (WARN_ON_ONCE(lock_is_write_held))
+ lwsp->n_lock_fail++;
+ lock_is_write_held = 1;
+ if (WARN_ON_ONCE(lock_is_read_held))
+ lwsp->n_lock_fail++; /* rare, but... */
+
+ lwsp->n_lock_acquired++;
+ cxt.cur_ops->write_delay(&rand);
+ lock_is_write_held = 0;
+ cxt.cur_ops->writeunlock();
+
+ stutter_wait("lock_torture_writer");
+ } while (!torture_must_stop());
+
+ cxt.cur_ops->task_boost(NULL); /* reset prio */
+ torture_kthread_stopping("lock_torture_writer");
+ return 0;
+}
+
+/*
+ * Lock torture reader kthread. Repeatedly acquires and releases
+ * the reader lock.
+ */
+static int lock_torture_reader(void *arg)
+{
+ struct lock_stress_stats *lrsp = arg;
+ static DEFINE_TORTURE_RANDOM(rand);
+
+ VERBOSE_TOROUT_STRING("lock_torture_reader task started");
+ set_user_nice(current, MAX_NICE);
+
+ do {
+ if ((torture_random(&rand) & 0xfffff) == 0)
+ schedule_timeout_uninterruptible(1);
+
+ cxt.cur_ops->readlock();
+ lock_is_read_held = 1;
+ if (WARN_ON_ONCE(lock_is_write_held))
+ lrsp->n_lock_fail++; /* rare, but... */
+
+ lrsp->n_lock_acquired++;
+ cxt.cur_ops->read_delay(&rand);
+ lock_is_read_held = 0;
+ cxt.cur_ops->readunlock();
+
+ stutter_wait("lock_torture_reader");
+ } while (!torture_must_stop());
+ torture_kthread_stopping("lock_torture_reader");
+ return 0;
+}
+
+/*
+ * Create an lock-torture-statistics message in the specified buffer.
+ */
+static void __torture_print_stats(char *page,
+ struct lock_stress_stats *statp, bool write)
+{
+ bool fail = 0;
+ int i, n_stress;
+ long max = 0, min = statp ? statp[0].n_lock_acquired : 0;
+ long long sum = 0;
+
+ n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
+ for (i = 0; i < n_stress; i++) {
+ if (statp[i].n_lock_fail)
+ fail = true;
+ sum += statp[i].n_lock_acquired;
+ if (max < statp[i].n_lock_fail)
+ max = statp[i].n_lock_fail;
+ if (min > statp[i].n_lock_fail)
+ min = statp[i].n_lock_fail;
+ }
+ page += sprintf(page,
+ "%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
+ write ? "Writes" : "Reads ",
+ sum, max, min, max / 2 > min ? "???" : "",
+ fail, fail ? "!!!" : "");
+ if (fail)
+ atomic_inc(&cxt.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 = cxt.nrealwriters_stress * 200 + 8192;
+ char *buf;
+
+ if (cxt.cur_ops->readlock)
+ size += cxt.nrealreaders_stress * 200 + 8192;
+
+ buf = kmalloc(size, GFP_KERNEL);
+ if (!buf) {
+ pr_err("lock_torture_stats_print: Out of memory, need: %d",
+ size);
+ return;
+ }
+
+ __torture_print_stats(buf, cxt.lwsa, true);
+ pr_alert("%s", buf);
+ kfree(buf);
+
+ if (cxt.cur_ops->readlock) {
+ buf = kmalloc(size, GFP_KERNEL);
+ if (!buf) {
+ pr_err("lock_torture_stats_print: Out of memory, need: %d",
+ size);
+ return;
+ }
+
+ __torture_print_stats(buf, cxt.lrsa, false);
+ 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 nreaders_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, cxt.debug_lock ? " [debug]": "",
+ cxt.nrealwriters_stress, cxt.nrealreaders_stress, stat_interval,
+ verbose, shuffle_interval, stutter, shutdown_secs,
+ onoff_interval, onoff_holdoff);
+}
+
+static void lock_torture_cleanup(void)
+{
+ int i;
+
+ if (torture_cleanup_begin())
+ return;
+
+ /*
+ * Indicates early cleanup, meaning that the test has not run,
+ * such as when passing bogus args when loading the module. As
+ * such, only perform the underlying torture-specific cleanups,
+ * and avoid anything related to locktorture.
+ */
+ if (!cxt.lwsa && !cxt.lrsa)
+ goto end;
+
+ if (writer_tasks) {
+ for (i = 0; i < cxt.nrealwriters_stress; i++)
+ torture_stop_kthread(lock_torture_writer,
+ writer_tasks[i]);
+ kfree(writer_tasks);
+ writer_tasks = NULL;
+ }
+
+ if (reader_tasks) {
+ for (i = 0; i < cxt.nrealreaders_stress; i++)
+ torture_stop_kthread(lock_torture_reader,
+ reader_tasks[i]);
+ kfree(reader_tasks);
+ reader_tasks = NULL;
+ }
+
+ torture_stop_kthread(lock_torture_stats, stats_task);
+ lock_torture_stats_print(); /* -After- the stats thread is stopped! */
+
+ if (atomic_read(&cxt.n_lock_torture_errors))
+ lock_torture_print_module_parms(cxt.cur_ops,
+ "End of test: FAILURE");
+ else if (torture_onoff_failures())
+ lock_torture_print_module_parms(cxt.cur_ops,
+ "End of test: LOCK_HOTPLUG");
+ else
+ lock_torture_print_module_parms(cxt.cur_ops,
+ "End of test: SUCCESS");
+
+ kfree(cxt.lwsa);
+ kfree(cxt.lrsa);
+
+end:
+ torture_cleanup_end();
+}
+
+static int __init lock_torture_init(void)
+{
+ int i, j;
+ int firsterr = 0;
+ static struct lock_torture_ops *torture_ops[] = {
+ &lock_busted_ops,
+ &spin_lock_ops, &spin_lock_irq_ops,
+ &rw_lock_ops, &rw_lock_irq_ops,
+ &mutex_lock_ops,
+ &ww_mutex_lock_ops,
+#ifdef CONFIG_RT_MUTEXES
+ &rtmutex_lock_ops,
+#endif
+ &rwsem_lock_ops,
+ &percpu_rwsem_lock_ops,
+ };
+
+ if (!torture_init_begin(torture_type, verbose))
+ return -EBUSY;
+
+ /* Process args and tell the world that the torturer is on the job. */
+ for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
+ cxt.cur_ops = torture_ops[i];
+ if (strcmp(torture_type, cxt.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");
+ firsterr = -EINVAL;
+ goto unwind;
+ }
+
+ if (nwriters_stress == 0 && nreaders_stress == 0) {
+ pr_alert("lock-torture: must run at least one locking thread\n");
+ firsterr = -EINVAL;
+ goto unwind;
+ }
+
+ if (cxt.cur_ops->init)
+ cxt.cur_ops->init();
+
+ if (nwriters_stress >= 0)
+ cxt.nrealwriters_stress = nwriters_stress;
+ else
+ cxt.nrealwriters_stress = 2 * num_online_cpus();
+
+#ifdef CONFIG_DEBUG_MUTEXES
+ if (strncmp(torture_type, "mutex", 5) == 0)
+ cxt.debug_lock = true;
+#endif
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+ if (strncmp(torture_type, "rtmutex", 7) == 0)
+ cxt.debug_lock = true;
+#endif
+#ifdef CONFIG_DEBUG_SPINLOCK
+ if ((strncmp(torture_type, "spin", 4) == 0) ||
+ (strncmp(torture_type, "rw_lock", 7) == 0))
+ cxt.debug_lock = true;
+#endif
+
+ /* Initialize the statistics so that each run gets its own numbers. */
+ if (nwriters_stress) {
+ lock_is_write_held = 0;
+ cxt.lwsa = kmalloc_array(cxt.nrealwriters_stress,
+ sizeof(*cxt.lwsa),
+ GFP_KERNEL);
+ if (cxt.lwsa == NULL) {
+ VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
+ firsterr = -ENOMEM;
+ goto unwind;
+ }
+
+ for (i = 0; i < cxt.nrealwriters_stress; i++) {
+ cxt.lwsa[i].n_lock_fail = 0;
+ cxt.lwsa[i].n_lock_acquired = 0;
+ }
+ }
+
+ if (cxt.cur_ops->readlock) {
+ if (nreaders_stress >= 0)
+ cxt.nrealreaders_stress = nreaders_stress;
+ else {
+ /*
+ * By default distribute evenly the number of
+ * readers and writers. We still run the same number
+ * of threads as the writer-only locks default.
+ */
+ if (nwriters_stress < 0) /* user doesn't care */
+ cxt.nrealwriters_stress = num_online_cpus();
+ cxt.nrealreaders_stress = cxt.nrealwriters_stress;
+ }
+
+ if (nreaders_stress) {
+ lock_is_read_held = 0;
+ cxt.lrsa = kmalloc_array(cxt.nrealreaders_stress,
+ sizeof(*cxt.lrsa),
+ GFP_KERNEL);
+ if (cxt.lrsa == NULL) {
+ VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
+ firsterr = -ENOMEM;
+ kfree(cxt.lwsa);
+ cxt.lwsa = NULL;
+ goto unwind;
+ }
+
+ for (i = 0; i < cxt.nrealreaders_stress; i++) {
+ cxt.lrsa[i].n_lock_fail = 0;
+ cxt.lrsa[i].n_lock_acquired = 0;
+ }
+ }
+ }
+
+ lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
+
+ /* Prepare torture context. */
+ 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;
+ }
+
+ if (nwriters_stress) {
+ writer_tasks = kcalloc(cxt.nrealwriters_stress,
+ sizeof(writer_tasks[0]),
+ GFP_KERNEL);
+ if (writer_tasks == NULL) {
+ VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
+ firsterr = -ENOMEM;
+ goto unwind;
+ }
+ }
+
+ if (cxt.cur_ops->readlock) {
+ reader_tasks = kcalloc(cxt.nrealreaders_stress,
+ sizeof(reader_tasks[0]),
+ GFP_KERNEL);
+ if (reader_tasks == NULL) {
+ VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");
+ kfree(writer_tasks);
+ writer_tasks = NULL;
+ firsterr = -ENOMEM;
+ goto unwind;
+ }
+ }
+
+ /*
+ * Create the kthreads and start torturing (oh, those poor little locks).
+ *
+ * TODO: Note that we interleave writers with readers, giving writers a
+ * slight advantage, by creating its kthread first. This can be modified
+ * for very specific needs, or even let the user choose the policy, if
+ * ever wanted.
+ */
+ for (i = 0, j = 0; i < cxt.nrealwriters_stress ||
+ j < cxt.nrealreaders_stress; i++, j++) {
+ if (i >= cxt.nrealwriters_stress)
+ goto create_reader;
+
+ /* Create writer. */
+ firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i],
+ writer_tasks[i]);
+ if (firsterr)
+ goto unwind;
+
+ create_reader:
+ if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress))
+ continue;
+ /* Create reader. */
+ firsterr = torture_create_kthread(lock_torture_reader, &cxt.lrsa[j],
+ reader_tasks[j]);
+ 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);