locktorture: Add a lock-torture kernel module (0af3fe1e) · Commits · e / devices / android_kernel_fairphone_FP3

kernel/locking/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -23,3 +23,4 @@ obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
		obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
		obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o
		obj-$(CONFIG_PERCPU_RWSEM) += percpu-rwsem.o
		obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o

kernel/locking/locktorture.c

0 → 100644

+421 −0

Original line number	Diff line number	Diff line
		/*
		* 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 <paulmck@us.ibm.com>
		* Based on kernel/rcu/torture.c.
		*/
		#include <linux/types.h>
		#include <linux/kernel.h>
		#include <linux/init.h>
		#include <linux/module.h>
		#include <linux/kthread.h>
		#include <linux/err.h>
		#include <linux/spinlock.h>
		#include <linux/smp.h>
		#include <linux/interrupt.h>
		#include <linux/sched.h>
		#include <linux/atomic.h>
		#include <linux/bitops.h>
		#include <linux/completion.h>
		#include <linux/moduleparam.h>
		#include <linux/percpu.h>
		#include <linux/notifier.h>
		#include <linux/reboot.h>
		#include <linux/freezer.h>
		#include <linux/cpu.h>
		#include <linux/delay.h>
		#include <linux/stat.h>
		#include <linux/slab.h>
		#include <linux/trace_clock.h>
		#include <asm/byteorder.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, 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 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, ...)");

		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_writer_stress_stats {
		long n_write_lock_fail;
		long n_write_lock_acquired;
		};
		static struct lock_writer_stress_stats *lwsa;

		#if defined(MODULE) \|\| defined(CONFIG_LOCK_TORTURE_TEST_RUNNABLE)
		#define LOCKTORTURE_RUNNABLE_INIT 1
		#else
		#define LOCKTORTURE_RUNNABLE_INIT 0
		#endif
		int locktorture_runnable = LOCKTORTURE_RUNNABLE_INIT;
		module_param(locktorture_runnable, int, 0444);
		MODULE_PARM_DESC(locktorture_runnable, "Start locktorture at boot");

		/* 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 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"
		};

		/*
		* Lock torture writer kthread. Repeatedly acquires and releases
		* the lock, checking for duplicate acquisitions.
		*/
		static int lock_torture_writer(void *arg)
		{
		struct lock_writer_stress_stats *lwsp = arg;
		static DEFINE_TORTURE_RANDOM(rand);

		VERBOSE_TOROUT_STRING("lock_torture_writer task started");
		set_user_nice(current, 19);

		do {
		schedule_timeout_uninterruptible(1);
		cur_ops->writelock();
		if (WARN_ON_ONCE(lock_is_write_held))
		lwsp->n_write_lock_fail++;
		lock_is_write_held = 1;
		lwsp->n_write_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_write_lock_acquired;
		long long sum = 0;

		for (i = 0; i < nrealwriters_stress; i++) {
		if (lwsa[i].n_write_lock_fail)
		fail = true;
		sum += lwsa[i].n_write_lock_acquired;
		if (max < lwsa[i].n_write_lock_fail)
		max = lwsa[i].n_write_lock_fail;
		if (min > lwsa[i].n_write_lock_fail)
		min = lwsa[i].n_write_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: 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, 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[] = {
		&spin_lock_ops, &spin_lock_irq_ops,
		};

		torture_init_begin(torture_type, verbose, &locktorture_runnable);

		/* 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();
		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_write_lock_fail = 0;
		lwsa[i].n_write_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);

lib/Kconfig.debug

+15 −0

Original line number	Diff line number	Diff line
		@@ -980,6 +980,21 @@ config DEBUG_LOCKING_API_SELFTESTS
		The following locking APIs are covered: spinlocks, rwlocks,
		mutexes and rwsems.

		config LOCK_TORTURE_TEST
		tristate "torture tests for locking"
		depends on DEBUG_KERNEL
		select TORTURE_TEST
		default n
		help
		This option provides a kernel module that runs torture tests
		on kernel locking primitives. The kernel module may be built
		after the fact on the running kernel to be tested, if desired.

		Say Y here if you want kernel locking-primitive torture tests
		to be built into the kernel.
		Say M if you want these torture tests to build as a module.
		Say N if you are unsure.

		endmenu # lock debugging

		config TRACE_IRQFLAGS