diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 13 | ||||
| -rw-r--r-- | lib/debug_locks.c | 2 | ||||
| -rw-r--r-- | lib/locking-selftest.c | 720 |
3 files changed, 717 insertions, 18 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 566cf2b..7154f79 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -547,6 +547,19 @@ config DEBUG_MUTEXES This feature allows mutex semantics violations to be detected and reported. +config DEBUG_WW_MUTEX_SLOWPATH + bool "Wait/wound mutex debugging: Slowpath testing" + depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT + select DEBUG_LOCK_ALLOC + select DEBUG_SPINLOCK + select DEBUG_MUTEXES + help + This feature enables slowpath testing for w/w mutex users by + injecting additional -EDEADLK wound/backoff cases. Together with + the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this + will test all possible w/w mutex interface abuse with the + exception of simply not acquiring all the required locks. + config DEBUG_LOCK_ALLOC bool "Lock debugging: detect incorrect freeing of live locks" depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT diff --git a/lib/debug_locks.c b/lib/debug_locks.c index f2fa60c..96c4c63 100644 --- a/lib/debug_locks.c +++ b/lib/debug_locks.c @@ -30,6 +30,7 @@ EXPORT_SYMBOL_GPL(debug_locks); * a locking bug is detected. */ int debug_locks_silent; +EXPORT_SYMBOL_GPL(debug_locks_silent); /* * Generic 'turn off all lock debugging' function: @@ -44,3 +45,4 @@ int debug_locks_off(void) } return 0; } +EXPORT_SYMBOL_GPL(debug_locks_off); diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c index c3eb261..aad024d 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, o3; /* * Normal standalone locks, for the circular and irq-context @@ -193,6 +199,20 @@ static void init_shared_classes(void) #define RSU(x) up_read(&rwsem_##x) #define RWSI(x) init_rwsem(&rwsem_##x) +#ifndef CONFIG_DEBUG_WW_MUTEX_SLOWPATH +#define WWAI(x) ww_acquire_init(x, &ww_lockdep) +#else +#define WWAI(x) do { ww_acquire_init(x, &ww_lockdep); (x)->deadlock_inject_countdown = ~0U; } while (0) +#endif +#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 +914,13 @@ 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 +942,20 @@ 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); I_WW(o3.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); ww_mutex_init(&o3, &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 +969,6 @@ 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()); @@ -947,25 +977,17 @@ static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask) * Filter out expected failures: */ #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; + if (expected == FAILURE && debug_locks) { + expected_testcase_failures++; + printk("failed|"); + } + else #endif if (debug_locks != expected) { - if (expected_failure) { - expected_testcase_failures++; - printk("failed|"); - } else { - unexpected_testcase_failures++; - - printk("FAILED|"); - dump_stack(); - } + unexpected_testcase_failures++; + printk("FAILED|"); + + dump_stack(); } else { testcase_successes++; printk(" ok |"); @@ -1108,6 +1130,666 @@ 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); + + /* + * None of the ww_mutex codepaths should be taken in the 'normal' + * mutex calls. The easiest way to verify this is by using the + * normal mutex calls, and making sure o.ctx is unmodified. + */ + + /* 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); +} + +static void ww_test_two_contexts(void) +{ + WWAI(&t); + WWAI(&t2); +} + +static void ww_test_diff_class(void) +{ + WWAI(&t); +#ifdef CONFIG_DEBUG_MUTEXES + t.ww_class = NULL; +#endif + WWL(&o, &t); +} + +static void ww_test_context_done_twice(void) +{ + WWAI(&t); + WWAD(&t); + WWAD(&t); + WWAF(&t); +} + +static void ww_test_context_unlock_twice(void) +{ + WWAI(&t); + WWAD(&t); + WWAF(&t); + WWAF(&t); +} + +static void ww_test_context_fini_early(void) +{ + WWAI(&t); + WWL(&o, &t); + WWAD(&t); + WWAF(&t); +} + +static void ww_test_context_lock_after_done(void) +{ + WWAI(&t); + WWAD(&t); + WWL(&o, &t); +} + +static void ww_test_object_unlock_twice(void) +{ + WWL1(&o); + WWU(&o); + WWU(&o); +} + +static void ww_test_object_lock_unbalanced(void) +{ + WWAI(&t); + WWL(&o, &t); + t.acquired = 0; + WWU(&o); + WWAF(&t); +} + +static void ww_test_object_lock_stale_context(void) +{ + WWAI(&t); + o.ctx = &t2; + WWL(&o, &t); +} + +static void ww_test_edeadlk_normal(void) +{ + int ret; + + mutex_lock(&o2.base); + o2.ctx = &t2; + mutex_release(&o2.base.dep_map, 1, _THIS_IP_); + + WWAI(&t); + t2 = t; + t2.stamp--; + + ret = WWL(&o, &t); + WARN_ON(ret); + + ret = WWL(&o2, &t); + WARN_ON(ret != -EDEADLK); + + o2.ctx = NULL; + mutex_acquire(&o2.base.dep_map, 0, 1, _THIS_IP_); + mutex_unlock(&o2.base); + WWU(&o); + + WWL(&o2, &t); +} + +static void ww_test_edeadlk_normal_slow(void) +{ + int ret; + + mutex_lock(&o2.base); + mutex_release(&o2.base.dep_map, 1, _THIS_IP_); + o2.ctx = &t2; + + WWAI(&t); + t2 = t; + t2.stamp--; + + ret = WWL(&o, &t); + WARN_ON(ret); + + ret = WWL(&o2, &t); + WARN_ON(ret != -EDEADLK); + + o2.ctx = NULL; + mutex_acquire(&o2.base.dep_map, 0, 1, _THIS_IP_); + mutex_unlock(&o2.base); + WWU(&o); + + ww_mutex_lock_slow(&o2, &t); +} + +static void ww_test_edeadlk_no_unlock(void) +{ + int ret; + + mutex_lock(&o2.base); + o2.ctx = &t2; + mutex_release(&o2.base.dep_map, 1, _THIS_IP_); + + WWAI(&t); + t2 = t; + t2.stamp--; + + ret = WWL(&o, &t); + WARN_ON(ret); + + ret = WWL(&o2, &t); + WARN_ON(ret != -EDEADLK); + + o2.ctx = NULL; + mutex_acquire(&o2.base.dep_map, 0, 1, _THIS_IP_); + mutex_unlock(&o2.base); + + WWL(&o2, &t); +} + +static void ww_test_edeadlk_no_unlock_slow(void) +{ + int ret; + + mutex_lock(&o2.base); + mutex_release(&o2.base.dep_map, 1, _THIS_IP_); + o2.ctx = &t2; + + WWAI(&t); + t2 = t; + t2.stamp--; + + ret = WWL(&o, &t); + WARN_ON(ret); + + ret = WWL(&o2, &t); + WARN_ON(ret != -EDEADLK); + + o2.ctx = NULL; + mutex_acquire(&o2.base.dep_map, 0, 1, _THIS_IP_); + mutex_unlock(&o2.base); + + ww_mutex_lock_slow(&o2, &t); +} + +static void ww_test_edeadlk_acquire_more(void) +{ + int ret; + + mutex_lock(&o2.base); + mutex_release(&o2.base.dep_map, 1, _THIS_IP_); + o2.ctx = &t2; + + WWAI(&t); + t2 = t; + t2.stamp--; + + ret = WWL(&o, &t); + WARN_ON(ret); + + ret = WWL(&o2, &t); + WARN_ON(ret != -EDEADLK); + + ret = WWL(&o3, &t); +} + +static void ww_test_edeadlk_acquire_more_slow(void) +{ + int ret; + + mutex_lock(&o2.base); + mutex_release(&o2.base.dep_map, 1, _THIS_IP_); + o2.ctx = &t2; + + WWAI(&t); + t2 = t; + t2.stamp--; + + ret = WWL(&o, &t); + WARN_ON(ret); + + ret = WWL(&o2, &t); + WARN_ON(ret != -EDEADLK); + + ww_mutex_lock_slow(&o3, &t); +} + +static void ww_test_edeadlk_acquire_more_edeadlk(void) +{ + int ret; + + mutex_lock(&o2.base); + mutex_release(&o2.base.dep_map, 1, _THIS_IP_); + o2.ctx = &t2; + + mutex_lock(&o3.base); + mutex_release(&o3.base.dep_map, 1, _THIS_IP_); + o3.ctx = &t2; + + WWAI(&t); + t2 = t; + t2.stamp--; + + ret = WWL(&o, &t); + WARN_ON(ret); + + ret = WWL(&o2, &t); + WARN_ON(ret != -EDEADLK); + + ret = WWL(&o3, &t); + WARN_ON(ret != -EDEADLK); +} + +static void ww_test_edeadlk_acquire_more_edeadlk_slow(void) +{ + int ret; + + mutex_lock(&o2.base); + mutex_release(&o2.base.dep_map, 1, _THIS_IP_); + o2.ctx = &t2; + + mutex_lock(&o3.base); + mutex_release(&o3.base.dep_map, 1, _THIS_IP_); + o3.ctx = &t2; + + WWAI(&t); + t2 = t; + t2.stamp--; + + ret = WWL(&o, &t); + WARN_ON(ret); + + ret = WWL(&o2, &t); + WARN_ON(ret != -EDEADLK); + + ww_mutex_lock_slow(&o3, &t); +} + +static void ww_test_edeadlk_acquire_wrong(void) +{ + int ret; + + mutex_lock(&o2.base); + mutex_release(&o2.base.dep_map, 1, _THIS_IP_); + o2.ctx = &t2; + + WWAI(&t); + t2 = t; + t2.stamp--; + + ret = WWL(&o, &t); + WARN_ON(ret); + + ret = WWL(&o2, &t); + WARN_ON(ret != -EDEADLK); + if (!ret) + WWU(&o2); + + WWU(&o); + + ret = WWL(&o3, &t); +} + +static void ww_test_edeadlk_acquire_wrong_slow(void) +{ + int ret; + + mutex_lock(&o2.base); + mutex_release(&o2.base.dep_map, 1, _THIS_IP_); + o2.ctx = &t2; + + WWAI(&t); + t2 = t; + t2.stamp--; + + ret = WWL(&o, &t); + WARN_ON(ret); + + ret = WWL(&o2, &t); + WARN_ON(ret != -EDEADLK); + if (!ret) + WWU(&o2); + + WWU(&o); + + ww_mutex_lock_slow(&o3, &t); +} + +static void ww_test_spin_nest_unlocked(void) +{ + raw_spin_lock_nest_lock(&lock_A, &o.base); + U(A); +} + +static void ww_test_unneeded_slow(void) +{ + WWAI(&t); + + ww_mutex_lock_slow(&o, &t); +} + +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("ww contexts mixing"); + dotest(ww_test_two_contexts, FAILURE, LOCKTYPE_WW); + dotest(ww_test_diff_class, FAILURE, LOCKTYPE_WW); + printk("\n"); + + print_testname("finishing ww context"); + dotest(ww_test_context_done_twice, FAILURE, LOCKTYPE_WW); + dotest(ww_test_context_unlock_twice, FAILURE, LOCKTYPE_WW); + dotest(ww_test_context_fini_early, FAILURE, LOCKTYPE_WW); + dotest(ww_test_context_lock_after_done, FAILURE, LOCKTYPE_WW); + printk("\n"); + + print_testname("locking mismatches"); + dotest(ww_test_object_unlock_twice, FAILURE, LOCKTYPE_WW); + dotest(ww_test_object_lock_unbalanced, FAILURE, LOCKTYPE_WW); + dotest(ww_test_object_lock_stale_context, FAILURE, LOCKTYPE_WW); + printk("\n"); + + print_testname("EDEADLK handling"); + dotest(ww_test_edeadlk_normal, SUCCESS, LOCKTYPE_WW); + dotest(ww_test_edeadlk_normal_slow, SUCCESS, LOCKTYPE_WW); + dotest(ww_test_edeadlk_no_unlock, FAILURE, LOCKTYPE_WW); + dotest(ww_test_edeadlk_no_unlock_slow, FAILURE, LOCKTYPE_WW); + dotest(ww_test_edeadlk_acquire_more, FAILURE, LOCKTYPE_WW); + dotest(ww_test_edeadlk_acquire_more_slow, FAILURE, LOCKTYPE_WW); + dotest(ww_test_edeadlk_acquire_more_edeadlk, FAILURE, LOCKTYPE_WW); + dotest(ww_test_edeadlk_acquire_more_edeadlk_slow, FAILURE, LOCKTYPE_WW); + dotest(ww_test_edeadlk_acquire_wrong, FAILURE, LOCKTYPE_WW); + dotest(ww_test_edeadlk_acquire_wrong_slow, 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 +1870,8 @@ 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; |
