locktorture: Add a lock-torture kernel module
This commit adds the locking counterpart to rcutorture. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: Make n_lock_torture_errors and torture_spinlock static as suggested by Fengguang Wu. ] Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit is contained in:
Paul E. McKenney
parent
2193e1604e
commit
0af3fe1efa
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@ -23,3 +23,4 @@ obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
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obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
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obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o
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obj-$(CONFIG_PERCPU_RWSEM) += percpu-rwsem.o
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obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o
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@ -0,0 +1,421 @@
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/*
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* Module-based torture test facility for locking
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, you can access it online at
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* http://www.gnu.org/licenses/gpl-2.0.html.
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*
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* Copyright (C) IBM Corporation, 2014
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*
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* Author: Paul E. McKenney <paulmck@us.ibm.com>
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* Based on kernel/rcu/torture.c.
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/kthread.h>
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#include <linux/err.h>
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#include <linux/spinlock.h>
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#include <linux/smp.h>
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#include <linux/interrupt.h>
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#include <linux/sched.h>
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#include <linux/atomic.h>
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#include <linux/bitops.h>
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#include <linux/completion.h>
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#include <linux/moduleparam.h>
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#include <linux/percpu.h>
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#include <linux/notifier.h>
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#include <linux/reboot.h>
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#include <linux/freezer.h>
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#include <linux/cpu.h>
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#include <linux/delay.h>
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#include <linux/stat.h>
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#include <linux/slab.h>
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#include <linux/trace_clock.h>
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#include <asm/byteorder.h>
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#include <linux/torture.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
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torture_param(int, nwriters_stress, -1,
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"Number of write-locking stress-test threads");
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torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
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torture_param(int, onoff_interval, 0,
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"Time between CPU hotplugs (s), 0=disable");
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torture_param(int, shuffle_interval, 3,
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"Number of jiffies between shuffles, 0=disable");
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torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
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torture_param(int, stat_interval, 60,
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"Number of seconds between stats printk()s");
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torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
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torture_param(bool, verbose, true,
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"Enable verbose debugging printk()s");
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static char *torture_type = "spin_lock";
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module_param(torture_type, charp, 0444);
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MODULE_PARM_DESC(torture_type,
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"Type of lock to torture (spin_lock, spin_lock_irq, ...)");
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static atomic_t n_lock_torture_errors;
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static struct task_struct *stats_task;
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static struct task_struct **writer_tasks;
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static int nrealwriters_stress;
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static bool lock_is_write_held;
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struct lock_writer_stress_stats {
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long n_write_lock_fail;
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long n_write_lock_acquired;
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};
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static struct lock_writer_stress_stats *lwsa;
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#if defined(MODULE) || defined(CONFIG_LOCK_TORTURE_TEST_RUNNABLE)
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#define LOCKTORTURE_RUNNABLE_INIT 1
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#else
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#define LOCKTORTURE_RUNNABLE_INIT 0
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#endif
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int locktorture_runnable = LOCKTORTURE_RUNNABLE_INIT;
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module_param(locktorture_runnable, int, 0444);
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MODULE_PARM_DESC(locktorture_runnable, "Start locktorture at boot");
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/* Forward reference. */
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static void lock_torture_cleanup(void);
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/*
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* Operations vector for selecting different types of tests.
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*/
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struct lock_torture_ops {
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void (*init)(void);
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int (*writelock)(void);
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void (*write_delay)(struct torture_random_state *trsp);
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void (*writeunlock)(void);
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unsigned long flags;
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const char *name;
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};
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static struct lock_torture_ops *cur_ops;
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/*
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* Definitions for lock torture testing.
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*/
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static DEFINE_SPINLOCK(torture_spinlock);
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static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock)
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{
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spin_lock(&torture_spinlock);
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return 0;
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}
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static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
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{
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const unsigned long shortdelay_us = 2;
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const unsigned long longdelay_us = 100;
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/* We want a short delay mostly to emulate likely code, and
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* we want a long delay occasionally to force massive contention.
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*/
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if (!(torture_random(trsp) %
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(nrealwriters_stress * 2000 * longdelay_us)))
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mdelay(longdelay_us);
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if (!(torture_random(trsp) %
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(nrealwriters_stress * 2 * shortdelay_us)))
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udelay(shortdelay_us);
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#ifdef CONFIG_PREEMPT
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if (!(torture_random(trsp) % (nrealwriters_stress * 20000)))
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preempt_schedule(); /* Allow test to be preempted. */
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#endif
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}
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static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock)
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{
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spin_unlock(&torture_spinlock);
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}
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static struct lock_torture_ops spin_lock_ops = {
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.writelock = torture_spin_lock_write_lock,
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.write_delay = torture_spin_lock_write_delay,
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.writeunlock = torture_spin_lock_write_unlock,
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.name = "spin_lock"
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};
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static int torture_spin_lock_write_lock_irq(void)
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__acquires(torture_spinlock_irq)
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{
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unsigned long flags;
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spin_lock_irqsave(&torture_spinlock, flags);
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cur_ops->flags = flags;
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return 0;
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}
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static void torture_lock_spin_write_unlock_irq(void)
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__releases(torture_spinlock)
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{
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spin_unlock_irqrestore(&torture_spinlock, cur_ops->flags);
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}
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static struct lock_torture_ops spin_lock_irq_ops = {
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.writelock = torture_spin_lock_write_lock_irq,
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.write_delay = torture_spin_lock_write_delay,
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.writeunlock = torture_lock_spin_write_unlock_irq,
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.name = "spin_lock_irq"
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};
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/*
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* Lock torture writer kthread. Repeatedly acquires and releases
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* the lock, checking for duplicate acquisitions.
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*/
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static int lock_torture_writer(void *arg)
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{
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struct lock_writer_stress_stats *lwsp = arg;
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static DEFINE_TORTURE_RANDOM(rand);
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VERBOSE_TOROUT_STRING("lock_torture_writer task started");
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set_user_nice(current, 19);
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do {
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schedule_timeout_uninterruptible(1);
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cur_ops->writelock();
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if (WARN_ON_ONCE(lock_is_write_held))
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lwsp->n_write_lock_fail++;
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lock_is_write_held = 1;
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lwsp->n_write_lock_acquired++;
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cur_ops->write_delay(&rand);
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lock_is_write_held = 0;
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cur_ops->writeunlock();
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stutter_wait("lock_torture_writer");
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} while (!torture_must_stop());
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torture_kthread_stopping("lock_torture_writer");
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return 0;
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}
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/*
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* Create an lock-torture-statistics message in the specified buffer.
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*/
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static void lock_torture_printk(char *page)
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{
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bool fail = 0;
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int i;
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long max = 0;
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long min = lwsa[0].n_write_lock_acquired;
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long long sum = 0;
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for (i = 0; i < nrealwriters_stress; i++) {
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if (lwsa[i].n_write_lock_fail)
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fail = true;
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sum += lwsa[i].n_write_lock_acquired;
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if (max < lwsa[i].n_write_lock_fail)
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max = lwsa[i].n_write_lock_fail;
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if (min > lwsa[i].n_write_lock_fail)
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min = lwsa[i].n_write_lock_fail;
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}
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page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG);
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page += sprintf(page,
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"Writes: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
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sum, max, min, max / 2 > min ? "???" : "",
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fail, fail ? "!!!" : "");
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if (fail)
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atomic_inc(&n_lock_torture_errors);
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}
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/*
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* Print torture statistics. Caller must ensure that there is only one
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* call to this function at a given time!!! This is normally accomplished
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* by relying on the module system to only have one copy of the module
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* loaded, and then by giving the lock_torture_stats kthread full control
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* (or the init/cleanup functions when lock_torture_stats thread is not
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* running).
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*/
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static void lock_torture_stats_print(void)
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{
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int size = nrealwriters_stress * 200 + 8192;
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char *buf;
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buf = kmalloc(size, GFP_KERNEL);
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if (!buf) {
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pr_err("lock_torture_stats_print: Out of memory, need: %d",
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size);
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return;
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}
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lock_torture_printk(buf);
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pr_alert("%s", buf);
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kfree(buf);
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}
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/*
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* Periodically prints torture statistics, if periodic statistics printing
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* was specified via the stat_interval module parameter.
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*
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* No need to worry about fullstop here, since this one doesn't reference
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* volatile state or register callbacks.
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*/
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static int lock_torture_stats(void *arg)
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{
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VERBOSE_TOROUT_STRING("lock_torture_stats task started");
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do {
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schedule_timeout_interruptible(stat_interval * HZ);
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lock_torture_stats_print();
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torture_shutdown_absorb("lock_torture_stats");
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} while (!torture_must_stop());
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torture_kthread_stopping("lock_torture_stats");
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return 0;
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}
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static inline void
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lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
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const char *tag)
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{
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pr_alert("%s" TORTURE_FLAG
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"--- %s: nwriters_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
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torture_type, tag, nrealwriters_stress, stat_interval, verbose,
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shuffle_interval, stutter, shutdown_secs,
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onoff_interval, onoff_holdoff);
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}
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static void lock_torture_cleanup(void)
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{
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int i;
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if (torture_cleanup())
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return;
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if (writer_tasks) {
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for (i = 0; i < nrealwriters_stress; i++)
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torture_stop_kthread(lock_torture_writer,
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writer_tasks[i]);
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kfree(writer_tasks);
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writer_tasks = NULL;
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}
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torture_stop_kthread(lock_torture_stats, stats_task);
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lock_torture_stats_print(); /* -After- the stats thread is stopped! */
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if (atomic_read(&n_lock_torture_errors))
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lock_torture_print_module_parms(cur_ops,
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"End of test: FAILURE");
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else if (torture_onoff_failures())
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lock_torture_print_module_parms(cur_ops,
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"End of test: LOCK_HOTPLUG");
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else
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lock_torture_print_module_parms(cur_ops,
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"End of test: SUCCESS");
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}
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static int __init lock_torture_init(void)
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{
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int i;
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int firsterr = 0;
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static struct lock_torture_ops *torture_ops[] = {
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&spin_lock_ops, &spin_lock_irq_ops,
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};
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torture_init_begin(torture_type, verbose, &locktorture_runnable);
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/* Process args and tell the world that the torturer is on the job. */
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for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
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cur_ops = torture_ops[i];
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if (strcmp(torture_type, cur_ops->name) == 0)
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break;
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}
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if (i == ARRAY_SIZE(torture_ops)) {
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pr_alert("lock-torture: invalid torture type: \"%s\"\n",
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torture_type);
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pr_alert("lock-torture types:");
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for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
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pr_alert(" %s", torture_ops[i]->name);
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pr_alert("\n");
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torture_init_end();
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return -EINVAL;
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}
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if (cur_ops->init)
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cur_ops->init(); /* no "goto unwind" prior to this point!!! */
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if (nwriters_stress >= 0)
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nrealwriters_stress = nwriters_stress;
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else
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nrealwriters_stress = 2 * num_online_cpus();
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lock_torture_print_module_parms(cur_ops, "Start of test");
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/* Initialize the statistics so that each run gets its own numbers. */
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lock_is_write_held = 0;
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lwsa = kmalloc(sizeof(*lwsa) * nrealwriters_stress, GFP_KERNEL);
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if (lwsa == NULL) {
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VERBOSE_TOROUT_STRING("lwsa: Out of memory");
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firsterr = -ENOMEM;
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goto unwind;
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}
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for (i = 0; i < nrealwriters_stress; i++) {
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lwsa[i].n_write_lock_fail = 0;
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lwsa[i].n_write_lock_acquired = 0;
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}
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/* Start up the kthreads. */
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if (onoff_interval > 0) {
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firsterr = torture_onoff_init(onoff_holdoff * HZ,
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onoff_interval * HZ);
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if (firsterr)
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goto unwind;
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}
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if (shuffle_interval > 0) {
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firsterr = torture_shuffle_init(shuffle_interval);
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if (firsterr)
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goto unwind;
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}
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if (shutdown_secs > 0) {
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firsterr = torture_shutdown_init(shutdown_secs,
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lock_torture_cleanup);
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if (firsterr)
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goto unwind;
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}
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if (stutter > 0) {
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firsterr = torture_stutter_init(stutter);
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if (firsterr)
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goto unwind;
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}
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writer_tasks = kzalloc(nrealwriters_stress * sizeof(writer_tasks[0]),
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GFP_KERNEL);
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if (writer_tasks == NULL) {
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VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
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firsterr = -ENOMEM;
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goto unwind;
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}
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for (i = 0; i < nrealwriters_stress; i++) {
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firsterr = torture_create_kthread(lock_torture_writer, &lwsa[i],
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writer_tasks[i]);
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if (firsterr)
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goto unwind;
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}
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if (stat_interval > 0) {
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firsterr = torture_create_kthread(lock_torture_stats, NULL,
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stats_task);
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if (firsterr)
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goto unwind;
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}
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torture_init_end();
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return 0;
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unwind:
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torture_init_end();
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lock_torture_cleanup();
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return firsterr;
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}
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module_init(lock_torture_init);
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module_exit(lock_torture_cleanup);
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@ -980,6 +980,21 @@ config DEBUG_LOCKING_API_SELFTESTS
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The following locking APIs are covered: spinlocks, rwlocks,
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mutexes and rwsems.
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config LOCK_TORTURE_TEST
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tristate "torture tests for locking"
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depends on DEBUG_KERNEL
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select TORTURE_TEST
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default n
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help
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This option provides a kernel module that runs torture tests
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on kernel locking primitives. The kernel module may be built
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after the fact on the running kernel to be tested, if desired.
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Say Y here if you want kernel locking-primitive torture tests
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to be built into the kernel.
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Say M if you want these torture tests to build as a module.
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Say N if you are unsure.
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endmenu # lock debugging
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config TRACE_IRQFLAGS
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