[PATCH v4 3/4] mutex: Add ww tests to lib/locking-selftest.c. v4

Daniel Vetter daniel at ffwll.ch
Tue May 28 12:18:47 PDT 2013


On Tue, May 28, 2013 at 04:48:45PM +0200, Maarten Lankhorst wrote:
> This stresses the lockdep code in some ways specifically useful to
> ww_mutexes. It adds checks for most of the common locking errors.
> 
> Changes since v1:
>  - Add tests to verify reservation_id is untouched.
>  - Use L() and U() macros where possible.
> 
> Changes since v2:
>  - Use the ww_mutex api directly.
>  - Use macros for most of the code.
> Changes since v3:
>  - Rework tests for the api changes.
> 
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at canonical.com>
> ---
>  lib/locking-selftest.c |  405 ++++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 386 insertions(+), 19 deletions(-)
> 
> diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
> index c3eb261..b18f1d3 100644
> --- a/lib/locking-selftest.c
> +++ b/lib/locking-selftest.c
> @@ -26,6 +26,8 @@
>   */
>  static unsigned int debug_locks_verbose;
>  
> +static DEFINE_WW_CLASS(ww_lockdep);
> +
>  static int __init setup_debug_locks_verbose(char *str)
>  {
>  	get_option(&str, &debug_locks_verbose);
> @@ -42,6 +44,10 @@ __setup("debug_locks_verbose=", setup_debug_locks_verbose);
>  #define LOCKTYPE_RWLOCK	0x2
>  #define LOCKTYPE_MUTEX	0x4
>  #define LOCKTYPE_RWSEM	0x8
> +#define LOCKTYPE_WW	0x10
> +
> +static struct ww_acquire_ctx t, t2;
> +static struct ww_mutex o, o2;
>  
>  /*
>   * Normal standalone locks, for the circular and irq-context
> @@ -193,6 +199,16 @@ static void init_shared_classes(void)
>  #define RSU(x)			up_read(&rwsem_##x)
>  #define RWSI(x)			init_rwsem(&rwsem_##x)
>  
> +#define WWAI(x)			ww_acquire_init(x, &ww_lockdep)
> +#define WWAD(x)			ww_acquire_done(x)
> +#define WWAF(x)			ww_acquire_fini(x)
> +
> +#define WWL(x, c)		ww_mutex_lock(x, c)
> +#define WWT(x)			ww_mutex_trylock(x)
> +#define WWL1(x)			ww_mutex_lock(x, NULL)
> +#define WWU(x)			ww_mutex_unlock(x)
> +
> +
>  #define LOCK_UNLOCK_2(x,y)	LOCK(x); LOCK(y); UNLOCK(y); UNLOCK(x)
>  
>  /*
> @@ -894,11 +910,13 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion_soft)
>  # define I_RWLOCK(x)	lockdep_reset_lock(&rwlock_##x.dep_map)
>  # define I_MUTEX(x)	lockdep_reset_lock(&mutex_##x.dep_map)
>  # define I_RWSEM(x)	lockdep_reset_lock(&rwsem_##x.dep_map)
> +# define I_WW(x)	lockdep_reset_lock(&x.dep_map)
>  #else
>  # define I_SPINLOCK(x)
>  # define I_RWLOCK(x)
>  # define I_MUTEX(x)
>  # define I_RWSEM(x)
> +# define I_WW(x)
>  #endif
>  
>  #define I1(x)					\
> @@ -920,11 +938,20 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion_soft)
>  static void reset_locks(void)
>  {
>  	local_irq_disable();
> +	lockdep_free_key_range(&ww_lockdep.acquire_key, 1);
> +	lockdep_free_key_range(&ww_lockdep.mutex_key, 1);
> +
>  	I1(A); I1(B); I1(C); I1(D);
>  	I1(X1); I1(X2); I1(Y1); I1(Y2); I1(Z1); I1(Z2);
> +	I_WW(t); I_WW(t2); I_WW(o.base); I_WW(o2.base);
>  	lockdep_reset();
>  	I2(A); I2(B); I2(C); I2(D);
>  	init_shared_classes();
> +
> +	ww_mutex_init(&o, &ww_lockdep); ww_mutex_init(&o2, &ww_lockdep);
> +	memset(&t, 0, sizeof(t)); memset(&t2, 0, sizeof(t2));
> +	memset(&ww_lockdep.acquire_key, 0, sizeof(ww_lockdep.acquire_key));
> +	memset(&ww_lockdep.mutex_key, 0, sizeof(ww_lockdep.mutex_key));
>  	local_irq_enable();
>  }
>  
> @@ -938,7 +965,6 @@ static int unexpected_testcase_failures;
>  static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask)
>  {
>  	unsigned long saved_preempt_count = preempt_count();
> -	int expected_failure = 0;
>  
>  	WARN_ON(irqs_disabled());
>  
> @@ -946,26 +972,16 @@ static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask)
>  	/*
>  	 * Filter out expected failures:
>  	 */
> +	if (debug_locks != expected) {
>  #ifndef CONFIG_PROVE_LOCKING
> -	if ((lockclass_mask & LOCKTYPE_SPIN) && debug_locks != expected)
> -		expected_failure = 1;
> -	if ((lockclass_mask & LOCKTYPE_RWLOCK) && debug_locks != expected)
> -		expected_failure = 1;
> -	if ((lockclass_mask & LOCKTYPE_MUTEX) && debug_locks != expected)
> -		expected_failure = 1;
> -	if ((lockclass_mask & LOCKTYPE_RWSEM) && debug_locks != expected)
> -		expected_failure = 1;
> +		expected_testcase_failures++;
> +		printk("failed|");
> +#else
> +		unexpected_testcase_failures++;
> +		printk("FAILED|");
> +
> +		dump_stack();
>  #endif
> -	if (debug_locks != expected) {
> -		if (expected_failure) {
> -			expected_testcase_failures++;
> -			printk("failed|");
> -		} else {
> -			unexpected_testcase_failures++;
> -
> -			printk("FAILED|");
> -			dump_stack();
> -		}
>  	} else {
>  		testcase_successes++;
>  		printk("  ok  |");
> @@ -1108,6 +1124,355 @@ static inline void print_testname(const char *testname)
>  	DO_TESTCASE_6IRW(desc, name, 312);			\
>  	DO_TESTCASE_6IRW(desc, name, 321);
>  
> +static void ww_test_fail_acquire(void)
> +{
> +	int ret;
> +
> +	WWAI(&t);
> +	t.stamp++;
> +
> +	ret = WWL(&o, &t);
> +
> +	if (WARN_ON(!o.ctx) ||
> +	    WARN_ON(ret))
> +		return;
> +
> +	/* No lockdep test, pure API */
> +	ret = WWL(&o, &t);
> +	WARN_ON(ret != -EALREADY);
> +
> +	ret = WWT(&o);
> +	WARN_ON(ret);
> +
> +	t2 = t;
> +	t2.stamp++;
> +	ret = WWL(&o, &t2);
> +	WARN_ON(ret != -EDEADLK);
> +	WWU(&o);
> +
> +	if (WWT(&o))
> +		WWU(&o);
> +#ifdef CONFIG_DEBUG_LOCK_ALLOC
> +	else
> +		DEBUG_LOCKS_WARN_ON(1);
> +#endif
> +}
> +
> +static void ww_test_normal(void)
> +{
> +	int ret;
> +
> +	WWAI(&t);
> +
> +	/*
> +	 * test if ww_id is kept identical if not
> +	 * called with any of the ww_* locking calls
> +	 */
> +
> +	/* mutex_lock (and indirectly, mutex_lock_nested) */
> +	o.ctx = (void *)~0UL;
> +	mutex_lock(&o.base);
> +	mutex_unlock(&o.base);
> +	WARN_ON(o.ctx != (void *)~0UL);
> +
> +	/* mutex_lock_interruptible (and *_nested) */
> +	o.ctx = (void *)~0UL;
> +	ret = mutex_lock_interruptible(&o.base);
> +	if (!ret)
> +		mutex_unlock(&o.base);
> +	else
> +		WARN_ON(1);
> +	WARN_ON(o.ctx != (void *)~0UL);
> +
> +	/* mutex_lock_killable (and *_nested) */
> +	o.ctx = (void *)~0UL;
> +	ret = mutex_lock_killable(&o.base);
> +	if (!ret)
> +		mutex_unlock(&o.base);
> +	else
> +		WARN_ON(1);
> +	WARN_ON(o.ctx != (void *)~0UL);
> +
> +	/* trylock, succeeding */
> +	o.ctx = (void *)~0UL;
> +	ret = mutex_trylock(&o.base);
> +	WARN_ON(!ret);
> +	if (ret)
> +		mutex_unlock(&o.base);
> +	else
> +		WARN_ON(1);
> +	WARN_ON(o.ctx != (void *)~0UL);
> +
> +	/* trylock, failing */
> +	o.ctx = (void *)~0UL;
> +	mutex_lock(&o.base);
> +	ret = mutex_trylock(&o.base);
> +	WARN_ON(ret);
> +	mutex_unlock(&o.base);
> +	WARN_ON(o.ctx != (void *)~0UL);
> +
> +	/* nest_lock */
> +	o.ctx = (void *)~0UL;
> +	mutex_lock_nest_lock(&o.base, &t);
> +	mutex_unlock(&o.base);
> +	WARN_ON(o.ctx != (void *)~0UL);
> +}

Since we don't really allow this any more (instead allow ww_mutex_lock
without context) do we need this test here really?

> +
> +static void ww_test_two_contexts(void)
> +{
> +	WWAI(&t);
> +	WWAI(&t2);
> +}
> +
> +static void ww_test_context_unlock_twice(void)
> +{
> +	WWAI(&t);
> +	WWAD(&t);
> +	WWAF(&t);
> +	WWAF(&t);
> +}
> +
> +static void ww_test_object_unlock_twice(void)
> +{
> +	WWL1(&o);
> +	WWU(&o);
> +	WWU(&o);
> +}
> +
> +static void ww_test_spin_nest_unlocked(void)
> +{
> +	raw_spin_lock_nest_lock(&lock_A, &o.base);
> +	U(A);
> +}

I don't quite see the point of this one here ...

> +
> +static void ww_test_unneeded_slow(void)
> +{
> +	int ret;
> +
> +	WWAI(&t);
> +
> +	ww_mutex_lock_slow(&o, &t);
> +}

I think checking the _slow debug stuff would be neat, i.e.
- fail/success tests for properly unlocking all held locks
- fail/success tests for lock_slow acquiring the right lock.

Otherwise I didn't spot anything that seems missing in these self-tests
here.

Cheers, Daniel

> +
> +static void ww_test_context_block(void)
> +{
> +	int ret;
> +
> +	WWAI(&t);
> +
> +	ret = WWL(&o, &t);
> +	WARN_ON(ret);
> +	WWL1(&o2);
> +}
> +
> +static void ww_test_context_try(void)
> +{
> +	int ret;
> +
> +	WWAI(&t);
> +
> +	ret = WWL(&o, &t);
> +	WARN_ON(ret);
> +
> +	ret = WWT(&o2);
> +	WARN_ON(!ret);
> +	WWU(&o2);
> +	WWU(&o);
> +}
> +
> +static void ww_test_context_context(void)
> +{
> +	int ret;
> +
> +	WWAI(&t);
> +
> +	ret = WWL(&o, &t);
> +	WARN_ON(ret);
> +
> +	ret = WWL(&o2, &t);
> +	WARN_ON(ret);
> +
> +	WWU(&o2);
> +	WWU(&o);
> +}
> +
> +static void ww_test_try_block(void)
> +{
> +	bool ret;
> +
> +	ret = WWT(&o);
> +	WARN_ON(!ret);
> +
> +	WWL1(&o2);
> +	WWU(&o2);
> +	WWU(&o);
> +}
> +
> +static void ww_test_try_try(void)
> +{
> +	bool ret;
> +
> +	ret = WWT(&o);
> +	WARN_ON(!ret);
> +	ret = WWT(&o2);
> +	WARN_ON(!ret);
> +	WWU(&o2);
> +	WWU(&o);
> +}
> +
> +static void ww_test_try_context(void)
> +{
> +	int ret;
> +
> +	ret = WWT(&o);
> +	WARN_ON(!ret);
> +
> +	WWAI(&t);
> +
> +	ret = WWL(&o2, &t);
> +	WARN_ON(ret);
> +}
> +
> +static void ww_test_block_block(void)
> +{
> +	WWL1(&o);
> +	WWL1(&o2);
> +}
> +
> +static void ww_test_block_try(void)
> +{
> +	bool ret;
> +
> +	WWL1(&o);
> +	ret = WWT(&o2);
> +	WARN_ON(!ret);
> +}
> +
> +static void ww_test_block_context(void)
> +{
> +	int ret;
> +
> +	WWL1(&o);
> +	WWAI(&t);
> +
> +	ret = WWL(&o2, &t);
> +	WARN_ON(ret);
> +}
> +
> +static void ww_test_spin_block(void)
> +{
> +	L(A);
> +	U(A);
> +
> +	WWL1(&o);
> +	L(A);
> +	U(A);
> +	WWU(&o);
> +
> +	L(A);
> +	WWL1(&o);
> +	WWU(&o);
> +	U(A);
> +}
> +
> +static void ww_test_spin_try(void)
> +{
> +	bool ret;
> +
> +	L(A);
> +	U(A);
> +
> +	ret = WWT(&o);
> +	WARN_ON(!ret);
> +	L(A);
> +	U(A);
> +	WWU(&o);
> +
> +	L(A);
> +	ret = WWT(&o);
> +	WARN_ON(!ret);
> +	WWU(&o);
> +	U(A);
> +}
> +
> +static void ww_test_spin_context(void)
> +{
> +	int ret;
> +
> +	L(A);
> +	U(A);
> +
> +	WWAI(&t);
> +
> +	ret = WWL(&o, &t);
> +	WARN_ON(ret);
> +	L(A);
> +	U(A);
> +	WWU(&o);
> +
> +	L(A);
> +	ret = WWL(&o, &t);
> +	WARN_ON(ret);
> +	WWU(&o);
> +	U(A);
> +}
> +
> +static void ww_tests(void)
> +{
> +	printk("  --------------------------------------------------------------------------\n");
> +	printk("  | Wound/wait tests |\n");
> +	printk("  ---------------------\n");
> +
> +	print_testname("ww api failures");
> +	dotest(ww_test_fail_acquire, SUCCESS, LOCKTYPE_WW);
> +	dotest(ww_test_normal, SUCCESS, LOCKTYPE_WW);
> +	dotest(ww_test_unneeded_slow, FAILURE, LOCKTYPE_WW);
> +	printk("\n");
> +
> +	print_testname("using two ww contexts");
> +	dotest(ww_test_two_contexts, FAILURE, LOCKTYPE_WW);
> +	printk("\n");
> +
> +	print_testname("finish ww context twice");
> +	dotest(ww_test_context_unlock_twice, FAILURE, LOCKTYPE_WW);
> +	printk("\n");
> +
> +	print_testname("unlock twice");
> +	dotest(ww_test_object_unlock_twice, FAILURE, LOCKTYPE_WW);
> +	printk("\n");
> +
> +	print_testname("spinlock nest unlocked");
> +	dotest(ww_test_spin_nest_unlocked, FAILURE, LOCKTYPE_WW);
> +	printk("\n");
> +
> +	printk("  -----------------------------------------------------\n");
> +	printk("                                 |block | try  |context|\n");
> +	printk("  -----------------------------------------------------\n");
> +
> +	print_testname("context");
> +	dotest(ww_test_context_block, FAILURE, LOCKTYPE_WW);
> +	dotest(ww_test_context_try, SUCCESS, LOCKTYPE_WW);
> +	dotest(ww_test_context_context, SUCCESS, LOCKTYPE_WW);
> +	printk("\n");
> +
> +	print_testname("try");
> +	dotest(ww_test_try_block, FAILURE, LOCKTYPE_WW);
> +	dotest(ww_test_try_try, SUCCESS, LOCKTYPE_WW);
> +	dotest(ww_test_try_context, FAILURE, LOCKTYPE_WW);
> +	printk("\n");
> +
> +	print_testname("block");
> +	dotest(ww_test_block_block, FAILURE, LOCKTYPE_WW);
> +	dotest(ww_test_block_try, SUCCESS, LOCKTYPE_WW);
> +	dotest(ww_test_block_context, FAILURE, LOCKTYPE_WW);
> +	printk("\n");
> +
> +	print_testname("spinlock");
> +	dotest(ww_test_spin_block, FAILURE, LOCKTYPE_WW);
> +	dotest(ww_test_spin_try, SUCCESS, LOCKTYPE_WW);
> +	dotest(ww_test_spin_context, FAILURE, LOCKTYPE_WW);
> +	printk("\n");
> +}
>  
>  void locking_selftest(void)
>  {
> @@ -1188,6 +1553,8 @@ void locking_selftest(void)
>  	DO_TESTCASE_6x2("irq read-recursion", irq_read_recursion);
>  //	DO_TESTCASE_6x2B("irq read-recursion #2", irq_read_recursion2);
>  
> +	ww_tests();
> +
>  	if (unexpected_testcase_failures) {
>  		printk("-----------------------------------------------------------------\n");
>  		debug_locks = 0;
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch


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