diff options
Diffstat (limited to 'kernel/locking')
| -rw-r--r-- | kernel/locking/lockdep.c | 115 | ||||
| -rw-r--r-- | kernel/locking/lockdep_internals.h | 19 | ||||
| -rw-r--r-- | kernel/locking/lockdep_proc.c | 4 | ||||
| -rw-r--r-- | kernel/locking/mutex-debug.c | 9 | ||||
| -rw-r--r-- | kernel/locking/mutex.c | 48 | ||||
| -rw-r--r-- | kernel/locking/mutex.h | 3 | ||||
| -rw-r--r-- | kernel/locking/percpu-rwsem.c | 13 | ||||
| -rw-r--r-- | kernel/locking/rtmutex_api.c | 51 | ||||
| -rw-r--r-- | kernel/locking/rwsem.c | 35 | ||||
| -rw-r--r-- | kernel/locking/semaphore.c | 57 | ||||
| -rw-r--r-- | kernel/locking/ww_mutex.h | 16 |
11 files changed, 256 insertions, 114 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 58d78a33ac65..2d4c5bab5af8 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -219,6 +219,7 @@ static DECLARE_BITMAP(list_entries_in_use, MAX_LOCKDEP_ENTRIES); static struct hlist_head lock_keys_hash[KEYHASH_SIZE]; unsigned long nr_lock_classes; unsigned long nr_zapped_classes; +unsigned long nr_dynamic_keys; unsigned long max_lock_class_idx; struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; DECLARE_BITMAP(lock_classes_in_use, MAX_LOCKDEP_KEYS); @@ -296,33 +297,30 @@ static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) dst->nr += src->nr; } -struct lock_class_stats lock_stats(struct lock_class *class) +void lock_stats(struct lock_class *class, struct lock_class_stats *stats) { - struct lock_class_stats stats; int cpu, i; - memset(&stats, 0, sizeof(struct lock_class_stats)); + memset(stats, 0, sizeof(struct lock_class_stats)); for_each_possible_cpu(cpu) { struct lock_class_stats *pcs = &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; - for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) - stats.contention_point[i] += pcs->contention_point[i]; + for (i = 0; i < ARRAY_SIZE(stats->contention_point); i++) + stats->contention_point[i] += pcs->contention_point[i]; - for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) - stats.contending_point[i] += pcs->contending_point[i]; + for (i = 0; i < ARRAY_SIZE(stats->contending_point); i++) + stats->contending_point[i] += pcs->contending_point[i]; - lock_time_add(&pcs->read_waittime, &stats.read_waittime); - lock_time_add(&pcs->write_waittime, &stats.write_waittime); + lock_time_add(&pcs->read_waittime, &stats->read_waittime); + lock_time_add(&pcs->write_waittime, &stats->write_waittime); - lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); - lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); + lock_time_add(&pcs->read_holdtime, &stats->read_holdtime); + lock_time_add(&pcs->write_holdtime, &stats->write_holdtime); - for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) - stats.bounces[i] += pcs->bounces[i]; + for (i = 0; i < ARRAY_SIZE(stats->bounces); i++) + stats->bounces[i] += pcs->bounces[i]; } - - return stats; } void clear_lock_stats(struct lock_class *class) @@ -1238,6 +1236,7 @@ void lockdep_register_key(struct lock_class_key *key) goto out_unlock; } hlist_add_head_rcu(&key->hash_entry, hash_head); + nr_dynamic_keys++; out_unlock: graph_unlock(); restore_irqs: @@ -1977,41 +1976,6 @@ print_circular_bug_header(struct lock_list *entry, unsigned int depth, } /* - * We are about to add A -> B into the dependency graph, and in __bfs() a - * strong dependency path A -> .. -> B is found: hlock_class equals - * entry->class. - * - * If A -> .. -> B can replace A -> B in any __bfs() search (means the former - * is _stronger_ than or equal to the latter), we consider A -> B as redundant. - * For example if A -> .. -> B is -(EN)-> (i.e. A -(E*)-> .. -(*N)-> B), and A - * -> B is -(ER)-> or -(EN)->, then we don't need to add A -> B into the - * dependency graph, as any strong path ..-> A -> B ->.. we can get with - * having dependency A -> B, we could already get a equivalent path ..-> A -> - * .. -> B -> .. with A -> .. -> B. Therefore A -> B is redundant. - * - * We need to make sure both the start and the end of A -> .. -> B is not - * weaker than A -> B. For the start part, please see the comment in - * check_redundant(). For the end part, we need: - * - * Either - * - * a) A -> B is -(*R)-> (everything is not weaker than that) - * - * or - * - * b) A -> .. -> B is -(*N)-> (nothing is stronger than this) - * - */ -static inline bool hlock_equal(struct lock_list *entry, void *data) -{ - struct held_lock *hlock = (struct held_lock *)data; - - return hlock_class(hlock) == entry->class && /* Found A -> .. -> B */ - (hlock->read == 2 || /* A -> B is -(*R)-> */ - !entry->only_xr); /* A -> .. -> B is -(*N)-> */ -} - -/* * We are about to add B -> A into the dependency graph, and in __bfs() a * strong dependency path A -> .. -> B is found: hlock_class equals * entry->class. @@ -2916,6 +2880,41 @@ static inline bool usage_skip(struct lock_list *entry, void *mask) #ifdef CONFIG_LOCKDEP_SMALL /* + * We are about to add A -> B into the dependency graph, and in __bfs() a + * strong dependency path A -> .. -> B is found: hlock_class equals + * entry->class. + * + * If A -> .. -> B can replace A -> B in any __bfs() search (means the former + * is _stronger_ than or equal to the latter), we consider A -> B as redundant. + * For example if A -> .. -> B is -(EN)-> (i.e. A -(E*)-> .. -(*N)-> B), and A + * -> B is -(ER)-> or -(EN)->, then we don't need to add A -> B into the + * dependency graph, as any strong path ..-> A -> B ->.. we can get with + * having dependency A -> B, we could already get a equivalent path ..-> A -> + * .. -> B -> .. with A -> .. -> B. Therefore A -> B is redundant. + * + * We need to make sure both the start and the end of A -> .. -> B is not + * weaker than A -> B. For the start part, please see the comment in + * check_redundant(). For the end part, we need: + * + * Either + * + * a) A -> B is -(*R)-> (everything is not weaker than that) + * + * or + * + * b) A -> .. -> B is -(*N)-> (nothing is stronger than this) + * + */ +static inline bool hlock_equal(struct lock_list *entry, void *data) +{ + struct held_lock *hlock = (struct held_lock *)data; + + return hlock_class(hlock) == entry->class && /* Found A -> .. -> B */ + (hlock->read == 2 || /* A -> B is -(*R)-> */ + !entry->only_xr); /* A -> .. -> B is -(*N)-> */ +} + +/* * Check that the dependency graph starting at <src> can lead to * <target> or not. If it can, <src> -> <target> dependency is already * in the graph. @@ -5101,6 +5100,9 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, lockevent_inc(lockdep_nocheck); } + if (DEBUG_LOCKS_WARN_ON(subclass >= MAX_LOCKDEP_SUBCLASSES)) + return 0; + if (subclass < NR_LOCKDEP_CACHING_CLASSES) class = lock->class_cache[subclass]; /* @@ -6606,6 +6608,7 @@ void lockdep_unregister_key(struct lock_class_key *key) pf = get_pending_free(); __lockdep_free_key_range(pf, key, 1); need_callback = prepare_call_rcu_zapped(pf); + nr_dynamic_keys--; } lockdep_unlock(); raw_local_irq_restore(flags); @@ -6613,8 +6616,16 @@ void lockdep_unregister_key(struct lock_class_key *key) if (need_callback) call_rcu(&delayed_free.rcu_head, free_zapped_rcu); - /* Wait until is_dynamic_key() has finished accessing k->hash_entry. */ - synchronize_rcu(); + /* + * Wait until is_dynamic_key() has finished accessing k->hash_entry. + * + * Some operations like __qdisc_destroy() will call this in a debug + * kernel, and the network traffic is disabled while waiting, hence + * the delay of the wait matters in debugging cases. Currently use a + * synchronize_rcu_expedited() to speed up the wait at the cost of + * system IPIs. TODO: Replace RCU with hazptr for this. + */ + synchronize_rcu_expedited(); } EXPORT_SYMBOL_GPL(lockdep_unregister_key); diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h index 20f9ef58d3d0..0e5e6ffe91a3 100644 --- a/kernel/locking/lockdep_internals.h +++ b/kernel/locking/lockdep_internals.h @@ -47,29 +47,31 @@ enum { __LOCKF(USED_READ) }; +enum { #define LOCKDEP_STATE(__STATE) LOCKF_ENABLED_##__STATE | -static const unsigned long LOCKF_ENABLED_IRQ = + LOCKF_ENABLED_IRQ = #include "lockdep_states.h" - 0; + 0, #undef LOCKDEP_STATE #define LOCKDEP_STATE(__STATE) LOCKF_USED_IN_##__STATE | -static const unsigned long LOCKF_USED_IN_IRQ = + LOCKF_USED_IN_IRQ = #include "lockdep_states.h" - 0; + 0, #undef LOCKDEP_STATE #define LOCKDEP_STATE(__STATE) LOCKF_ENABLED_##__STATE##_READ | -static const unsigned long LOCKF_ENABLED_IRQ_READ = + LOCKF_ENABLED_IRQ_READ = #include "lockdep_states.h" - 0; + 0, #undef LOCKDEP_STATE #define LOCKDEP_STATE(__STATE) LOCKF_USED_IN_##__STATE##_READ | -static const unsigned long LOCKF_USED_IN_IRQ_READ = + LOCKF_USED_IN_IRQ_READ = #include "lockdep_states.h" - 0; + 0, #undef LOCKDEP_STATE +}; #define LOCKF_ENABLED_IRQ_ALL (LOCKF_ENABLED_IRQ | LOCKF_ENABLED_IRQ_READ) #define LOCKF_USED_IN_IRQ_ALL (LOCKF_USED_IN_IRQ | LOCKF_USED_IN_IRQ_READ) @@ -138,6 +140,7 @@ extern unsigned long nr_lock_classes; extern unsigned long nr_zapped_classes; extern unsigned long nr_zapped_lock_chains; extern unsigned long nr_list_entries; +extern unsigned long nr_dynamic_keys; long lockdep_next_lockchain(long i); unsigned long lock_chain_count(void); extern unsigned long nr_stack_trace_entries; diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c index 6db0f43fc4df..1916db9aa46b 100644 --- a/kernel/locking/lockdep_proc.c +++ b/kernel/locking/lockdep_proc.c @@ -286,6 +286,8 @@ static int lockdep_stats_show(struct seq_file *m, void *v) #endif seq_printf(m, " lock-classes: %11lu [max: %lu]\n", nr_lock_classes, MAX_LOCKDEP_KEYS); + seq_printf(m, " dynamic-keys: %11lu\n", + nr_dynamic_keys); seq_printf(m, " direct dependencies: %11lu [max: %lu]\n", nr_list_entries, MAX_LOCKDEP_ENTRIES); seq_printf(m, " indirect dependencies: %11lu\n", @@ -655,7 +657,7 @@ static int lock_stat_open(struct inode *inode, struct file *file) if (!test_bit(idx, lock_classes_in_use)) continue; iter->class = class; - iter->stats = lock_stats(class); + lock_stats(class, &iter->stats); iter++; } diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c index 6e6f6071cfa2..949103fd8e9b 100644 --- a/kernel/locking/mutex-debug.c +++ b/kernel/locking/mutex-debug.c @@ -53,17 +53,18 @@ void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter, { lockdep_assert_held(&lock->wait_lock); - /* Mark the current thread as blocked on the lock: */ - task->blocked_on = waiter; + /* Current thread can't be already blocked (since it's executing!) */ + DEBUG_LOCKS_WARN_ON(__get_task_blocked_on(task)); } void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter, struct task_struct *task) { + struct mutex *blocked_on = __get_task_blocked_on(task); + DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list)); DEBUG_LOCKS_WARN_ON(waiter->task != task); - DEBUG_LOCKS_WARN_ON(task->blocked_on != waiter); - task->blocked_on = NULL; + DEBUG_LOCKS_WARN_ON(blocked_on && blocked_on != lock); INIT_LIST_HEAD(&waiter->list); waiter->task = NULL; diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 555e2b3a665a..de7d6702cd96 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -29,6 +29,7 @@ #include <linux/interrupt.h> #include <linux/debug_locks.h> #include <linux/osq_lock.h> +#include <linux/hung_task.h> #define CREATE_TRACE_POINTS #include <trace/events/lock.h> @@ -190,9 +191,7 @@ static void __mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter, struct list_head *list) { -#ifdef CONFIG_DETECT_HUNG_TASK_BLOCKER - WRITE_ONCE(current->blocker_mutex, lock); -#endif + hung_task_set_blocker(lock, BLOCKER_TYPE_MUTEX); debug_mutex_add_waiter(lock, waiter, current); list_add_tail(&waiter->list, list); @@ -208,9 +207,7 @@ __mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter) __mutex_clear_flag(lock, MUTEX_FLAGS); debug_mutex_remove_waiter(lock, waiter, current); -#ifdef CONFIG_DETECT_HUNG_TASK_BLOCKER - WRITE_ONCE(current->blocker_mutex, NULL); -#endif + hung_task_clear_blocker(); } /* @@ -643,6 +640,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas goto err_early_kill; } + __set_task_blocked_on(current, lock); set_current_state(state); trace_contention_begin(lock, LCB_F_MUTEX); for (;;) { @@ -679,6 +677,12 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas first = __mutex_waiter_is_first(lock, &waiter); + /* + * As we likely have been woken up by task + * that has cleared our blocked_on state, re-set + * it to the lock we are trying to acquire. + */ + set_task_blocked_on(current, lock); set_current_state(state); /* * Here we order against unlock; we must either see it change @@ -690,8 +694,15 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas if (first) { trace_contention_begin(lock, LCB_F_MUTEX | LCB_F_SPIN); + /* + * mutex_optimistic_spin() can call schedule(), so + * clear blocked on so we don't become unselectable + * to run. + */ + clear_task_blocked_on(current, lock); if (mutex_optimistic_spin(lock, ww_ctx, &waiter)) break; + set_task_blocked_on(current, lock); trace_contention_begin(lock, LCB_F_MUTEX); } @@ -699,6 +710,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas } raw_spin_lock_irqsave(&lock->wait_lock, flags); acquired: + __clear_task_blocked_on(current, lock); __set_current_state(TASK_RUNNING); if (ww_ctx) { @@ -728,9 +740,11 @@ skip_wait: return 0; err: + __clear_task_blocked_on(current, lock); __set_current_state(TASK_RUNNING); __mutex_remove_waiter(lock, &waiter); err_early_kill: + WARN_ON(__get_task_blocked_on(current)); trace_contention_end(lock, ret); raw_spin_unlock_irqrestore_wake(&lock->wait_lock, flags, &wake_q); debug_mutex_free_waiter(&waiter); @@ -808,11 +822,12 @@ _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest) EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock); int __sched -mutex_lock_killable_nested(struct mutex *lock, unsigned int subclass) +_mutex_lock_killable(struct mutex *lock, unsigned int subclass, + struct lockdep_map *nest) { - return __mutex_lock(lock, TASK_KILLABLE, subclass, NULL, _RET_IP_); + return __mutex_lock(lock, TASK_KILLABLE, subclass, nest, _RET_IP_); } -EXPORT_SYMBOL_GPL(mutex_lock_killable_nested); +EXPORT_SYMBOL_GPL(_mutex_lock_killable); int __sched mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass) @@ -940,6 +955,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne next = waiter->task; debug_mutex_wake_waiter(lock, waiter); + __clear_task_blocked_on(next, lock); wake_q_add(&wake_q, next); } @@ -1062,6 +1078,7 @@ __ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock, #endif +#ifndef CONFIG_DEBUG_LOCK_ALLOC /** * mutex_trylock - try to acquire the mutex, without waiting * @lock: the mutex to be acquired @@ -1078,17 +1095,24 @@ __ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock, */ int __sched mutex_trylock(struct mutex *lock) { + MUTEX_WARN_ON(lock->magic != lock); + return __mutex_trylock(lock); +} +EXPORT_SYMBOL(mutex_trylock); +#else +int __sched _mutex_trylock_nest_lock(struct mutex *lock, struct lockdep_map *nest_lock) +{ bool locked; MUTEX_WARN_ON(lock->magic != lock); - locked = __mutex_trylock(lock); if (locked) - mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_); + mutex_acquire_nest(&lock->dep_map, 0, 1, nest_lock, _RET_IP_); return locked; } -EXPORT_SYMBOL(mutex_trylock); +EXPORT_SYMBOL(_mutex_trylock_nest_lock); +#endif #ifndef CONFIG_DEBUG_LOCK_ALLOC int __sched diff --git a/kernel/locking/mutex.h b/kernel/locking/mutex.h index cbff35b9b7ae..2e8080a9bee3 100644 --- a/kernel/locking/mutex.h +++ b/kernel/locking/mutex.h @@ -6,7 +6,7 @@ * * Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> */ - +#ifndef CONFIG_PREEMPT_RT /* * This is the control structure for tasks blocked on mutex, which resides * on the blocked task's kernel stack: @@ -70,3 +70,4 @@ extern void debug_mutex_init(struct mutex *lock, const char *name, # define debug_mutex_unlock(lock) do { } while (0) # define debug_mutex_init(lock, name, key) do { } while (0) #endif /* !CONFIG_DEBUG_MUTEXES */ +#endif /* CONFIG_PREEMPT_RT */ diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c index d6964fc29f51..ef234469baac 100644 --- a/kernel/locking/percpu-rwsem.c +++ b/kernel/locking/percpu-rwsem.c @@ -138,7 +138,8 @@ static int percpu_rwsem_wake_function(struct wait_queue_entry *wq_entry, return !reader; /* wake (readers until) 1 writer */ } -static void percpu_rwsem_wait(struct percpu_rw_semaphore *sem, bool reader) +static void percpu_rwsem_wait(struct percpu_rw_semaphore *sem, bool reader, + bool freeze) { DEFINE_WAIT_FUNC(wq_entry, percpu_rwsem_wake_function); bool wait; @@ -156,7 +157,8 @@ static void percpu_rwsem_wait(struct percpu_rw_semaphore *sem, bool reader) spin_unlock_irq(&sem->waiters.lock); while (wait) { - set_current_state(TASK_UNINTERRUPTIBLE); + set_current_state(TASK_UNINTERRUPTIBLE | + (freeze ? TASK_FREEZABLE : 0)); if (!smp_load_acquire(&wq_entry.private)) break; schedule(); @@ -164,7 +166,8 @@ static void percpu_rwsem_wait(struct percpu_rw_semaphore *sem, bool reader) __set_current_state(TASK_RUNNING); } -bool __sched __percpu_down_read(struct percpu_rw_semaphore *sem, bool try) +bool __sched __percpu_down_read(struct percpu_rw_semaphore *sem, bool try, + bool freeze) { if (__percpu_down_read_trylock(sem)) return true; @@ -174,7 +177,7 @@ bool __sched __percpu_down_read(struct percpu_rw_semaphore *sem, bool try) trace_contention_begin(sem, LCB_F_PERCPU | LCB_F_READ); preempt_enable(); - percpu_rwsem_wait(sem, /* .reader = */ true); + percpu_rwsem_wait(sem, /* .reader = */ true, freeze); preempt_disable(); trace_contention_end(sem, 0); @@ -237,7 +240,7 @@ void __sched percpu_down_write(struct percpu_rw_semaphore *sem) */ if (!__percpu_down_write_trylock(sem)) { trace_contention_begin(sem, LCB_F_PERCPU | LCB_F_WRITE); - percpu_rwsem_wait(sem, /* .reader = */ false); + percpu_rwsem_wait(sem, /* .reader = */ false, false); contended = true; } diff --git a/kernel/locking/rtmutex_api.c b/kernel/locking/rtmutex_api.c index 191e4720e546..bafd5af98eae 100644 --- a/kernel/locking/rtmutex_api.c +++ b/kernel/locking/rtmutex_api.c @@ -13,6 +13,24 @@ */ int max_lock_depth = 1024; +static const struct ctl_table rtmutex_sysctl_table[] = { + { + .procname = "max_lock_depth", + .data = &max_lock_depth, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, +}; + +static int __init init_rtmutex_sysctl(void) +{ + register_sysctl_init("kernel", rtmutex_sysctl_table); + return 0; +} + +subsys_initcall(init_rtmutex_sysctl); + /* * Debug aware fast / slowpath lock,trylock,unlock * @@ -544,12 +562,12 @@ int __sched mutex_lock_interruptible_nested(struct mutex *lock, } EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested); -int __sched mutex_lock_killable_nested(struct mutex *lock, - unsigned int subclass) +int __sched _mutex_lock_killable(struct mutex *lock, unsigned int subclass, + struct lockdep_map *nest_lock) { - return __mutex_lock_common(lock, TASK_KILLABLE, subclass, NULL, _RET_IP_); + return __mutex_lock_common(lock, TASK_KILLABLE, subclass, nest_lock, _RET_IP_); } -EXPORT_SYMBOL_GPL(mutex_lock_killable_nested); +EXPORT_SYMBOL_GPL(_mutex_lock_killable); void __sched mutex_lock_io_nested(struct mutex *lock, unsigned int subclass) { @@ -563,6 +581,21 @@ void __sched mutex_lock_io_nested(struct mutex *lock, unsigned int subclass) } EXPORT_SYMBOL_GPL(mutex_lock_io_nested); +int __sched _mutex_trylock_nest_lock(struct mutex *lock, + struct lockdep_map *nest_lock) +{ + int ret; + + if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES) && WARN_ON_ONCE(!in_task())) + return 0; + + ret = __rt_mutex_trylock(&lock->rtmutex); + if (ret) + mutex_acquire_nest(&lock->dep_map, 0, 1, nest_lock, _RET_IP_); + + return ret; +} +EXPORT_SYMBOL_GPL(_mutex_trylock_nest_lock); #else /* CONFIG_DEBUG_LOCK_ALLOC */ void __sched mutex_lock(struct mutex *lock) @@ -591,22 +624,16 @@ void __sched mutex_lock_io(struct mutex *lock) io_schedule_finish(token); } EXPORT_SYMBOL(mutex_lock_io); -#endif /* !CONFIG_DEBUG_LOCK_ALLOC */ int __sched mutex_trylock(struct mutex *lock) { - int ret; - if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES) && WARN_ON_ONCE(!in_task())) return 0; - ret = __rt_mutex_trylock(&lock->rtmutex); - if (ret) - mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_); - - return ret; + return __rt_mutex_trylock(&lock->rtmutex); } EXPORT_SYMBOL(mutex_trylock); +#endif /* !CONFIG_DEBUG_LOCK_ALLOC */ void __sched mutex_unlock(struct mutex *lock) { diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 2ddb827e3bea..24df4d98f7d2 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -27,6 +27,7 @@ #include <linux/export.h> #include <linux/rwsem.h> #include <linux/atomic.h> +#include <linux/hung_task.h> #include <trace/events/lock.h> #ifndef CONFIG_PREEMPT_RT @@ -181,11 +182,11 @@ static inline void rwsem_set_reader_owned(struct rw_semaphore *sem) __rwsem_set_reader_owned(sem, current); } -#ifdef CONFIG_DEBUG_RWSEMS +#if defined(CONFIG_DEBUG_RWSEMS) || defined(CONFIG_DETECT_HUNG_TASK_BLOCKER) /* * Return just the real task structure pointer of the owner */ -static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem) +struct task_struct *rwsem_owner(struct rw_semaphore *sem) { return (struct task_struct *) (atomic_long_read(&sem->owner) & ~RWSEM_OWNER_FLAGS_MASK); @@ -194,7 +195,7 @@ static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem) /* * Return true if the rwsem is owned by a reader. */ -static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem) +bool is_rwsem_reader_owned(struct rw_semaphore *sem) { /* * Check the count to see if it is write-locked. @@ -207,10 +208,10 @@ static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem) } /* - * With CONFIG_DEBUG_RWSEMS configured, it will make sure that if there - * is a task pointer in owner of a reader-owned rwsem, it will be the - * real owner or one of the real owners. The only exception is when the - * unlock is done by up_read_non_owner(). + * With CONFIG_DEBUG_RWSEMS or CONFIG_DETECT_HUNG_TASK_BLOCKER configured, + * it will make sure that the owner field of a reader-owned rwsem either + * points to a real reader-owner(s) or gets cleared. The only exception is + * when the unlock is done by up_read_non_owner(). */ static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem) { @@ -727,8 +728,6 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem) return ret; } -#define OWNER_SPINNABLE (OWNER_NULL | OWNER_WRITER | OWNER_READER) - static inline enum owner_state rwsem_owner_state(struct task_struct *owner, unsigned long flags) { @@ -835,7 +834,7 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem) enum owner_state owner_state; owner_state = rwsem_spin_on_owner(sem); - if (!(owner_state & OWNER_SPINNABLE)) + if (owner_state == OWNER_NONSPINNABLE) break; /* @@ -1065,10 +1064,13 @@ queue: wake_up_q(&wake_q); trace_contention_begin(sem, LCB_F_READ); + set_current_state(state); + + if (state == TASK_UNINTERRUPTIBLE) + hung_task_set_blocker(sem, BLOCKER_TYPE_RWSEM_READER); /* wait to be given the lock */ for (;;) { - set_current_state(state); if (!smp_load_acquire(&waiter.task)) { /* Matches rwsem_mark_wake()'s smp_store_release(). */ break; @@ -1083,8 +1085,12 @@ queue: } schedule_preempt_disabled(); lockevent_inc(rwsem_sleep_reader); + set_current_state(state); } + if (state == TASK_UNINTERRUPTIBLE) + hung_task_clear_blocker(); + __set_current_state(TASK_RUNNING); lockevent_inc(rwsem_rlock); trace_contention_end(sem, 0); @@ -1146,6 +1152,9 @@ rwsem_down_write_slowpath(struct rw_semaphore *sem, int state) set_current_state(state); trace_contention_begin(sem, LCB_F_WRITE); + if (state == TASK_UNINTERRUPTIBLE) + hung_task_set_blocker(sem, BLOCKER_TYPE_RWSEM_WRITER); + for (;;) { if (rwsem_try_write_lock(sem, &waiter)) { /* rwsem_try_write_lock() implies ACQUIRE on success */ @@ -1179,6 +1188,10 @@ rwsem_down_write_slowpath(struct rw_semaphore *sem, int state) trylock_again: raw_spin_lock_irq(&sem->wait_lock); } + + if (state == TASK_UNINTERRUPTIBLE) + hung_task_clear_blocker(); + __set_current_state(TASK_RUNNING); raw_spin_unlock_irq(&sem->wait_lock); lockevent_inc(rwsem_wlock); diff --git a/kernel/locking/semaphore.c b/kernel/locking/semaphore.c index de9117c0e671..3ef032e22f7e 100644 --- a/kernel/locking/semaphore.c +++ b/kernel/locking/semaphore.c @@ -34,6 +34,7 @@ #include <linux/spinlock.h> #include <linux/ftrace.h> #include <trace/events/lock.h> +#include <linux/hung_task.h> static noinline void __down(struct semaphore *sem); static noinline int __down_interruptible(struct semaphore *sem); @@ -41,6 +42,41 @@ static noinline int __down_killable(struct semaphore *sem); static noinline int __down_timeout(struct semaphore *sem, long timeout); static noinline void __up(struct semaphore *sem, struct wake_q_head *wake_q); +#ifdef CONFIG_DETECT_HUNG_TASK_BLOCKER +static inline void hung_task_sem_set_holder(struct semaphore *sem) +{ + WRITE_ONCE((sem)->last_holder, (unsigned long)current); +} + +static inline void hung_task_sem_clear_if_holder(struct semaphore *sem) +{ + if (READ_ONCE((sem)->last_holder) == (unsigned long)current) + WRITE_ONCE((sem)->last_holder, 0UL); +} + +unsigned long sem_last_holder(struct semaphore *sem) +{ + return READ_ONCE(sem->last_holder); +} +#else +static inline void hung_task_sem_set_holder(struct semaphore *sem) +{ +} +static inline void hung_task_sem_clear_if_holder(struct semaphore *sem) +{ +} +unsigned long sem_last_holder(struct semaphore *sem) +{ + return 0UL; +} +#endif + +static inline void __sem_acquire(struct semaphore *sem) +{ + sem->count--; + hung_task_sem_set_holder(sem); +} + /** * down - acquire the semaphore * @sem: the semaphore to be acquired @@ -59,7 +95,7 @@ void __sched down(struct semaphore *sem) might_sleep(); raw_spin_lock_irqsave(&sem->lock, flags); if (likely(sem->count > 0)) - sem->count--; + __sem_acquire(sem); else __down(sem); raw_spin_unlock_irqrestore(&sem->lock, flags); @@ -83,7 +119,7 @@ int __sched down_interruptible(struct semaphore *sem) might_sleep(); raw_spin_lock_irqsave(&sem->lock, flags); if (likely(sem->count > 0)) - sem->count--; + __sem_acquire(sem); else result = __down_interruptible(sem); raw_spin_unlock_irqrestore(&sem->lock, flags); @@ -110,7 +146,7 @@ int __sched down_killable(struct semaphore *sem) might_sleep(); raw_spin_lock_irqsave(&sem->lock, flags); if (likely(sem->count > 0)) - sem->count--; + __sem_acquire(sem); else result = __down_killable(sem); raw_spin_unlock_irqrestore(&sem->lock, flags); @@ -140,7 +176,7 @@ int __sched down_trylock(struct semaphore *sem) raw_spin_lock_irqsave(&sem->lock, flags); count = sem->count - 1; if (likely(count >= 0)) - sem->count = count; + __sem_acquire(sem); raw_spin_unlock_irqrestore(&sem->lock, flags); return (count < 0); @@ -165,7 +201,7 @@ int __sched down_timeout(struct semaphore *sem, long timeout) might_sleep(); raw_spin_lock_irqsave(&sem->lock, flags); if (likely(sem->count > 0)) - sem->count--; + __sem_acquire(sem); else result = __down_timeout(sem, timeout); raw_spin_unlock_irqrestore(&sem->lock, flags); @@ -187,6 +223,9 @@ void __sched up(struct semaphore *sem) DEFINE_WAKE_Q(wake_q); raw_spin_lock_irqsave(&sem->lock, flags); + + hung_task_sem_clear_if_holder(sem); + if (likely(list_empty(&sem->wait_list))) sem->count++; else @@ -228,8 +267,10 @@ static inline int __sched ___down_common(struct semaphore *sem, long state, raw_spin_unlock_irq(&sem->lock); timeout = schedule_timeout(timeout); raw_spin_lock_irq(&sem->lock); - if (waiter.up) + if (waiter.up) { + hung_task_sem_set_holder(sem); return 0; + } } timed_out: @@ -246,10 +287,14 @@ static inline int __sched __down_common(struct semaphore *sem, long state, { int ret; + hung_task_set_blocker(sem, BLOCKER_TYPE_SEM); + trace_contention_begin(sem, 0); ret = ___down_common(sem, state, timeout); trace_contention_end(sem, ret); + hung_task_clear_blocker(); + return ret; } diff --git a/kernel/locking/ww_mutex.h b/kernel/locking/ww_mutex.h index 37f025a096c9..086fd5487ca7 100644 --- a/kernel/locking/ww_mutex.h +++ b/kernel/locking/ww_mutex.h @@ -284,6 +284,12 @@ __ww_mutex_die(struct MUTEX *lock, struct MUTEX_WAITER *waiter, #ifndef WW_RT debug_mutex_wake_waiter(lock, waiter); #endif + /* + * When waking up the task to die, be sure to clear the + * blocked_on pointer. Otherwise we can see circular + * blocked_on relationships that can't resolve. + */ + __clear_task_blocked_on(waiter->task, lock); wake_q_add(wake_q, waiter->task); } @@ -331,9 +337,15 @@ static bool __ww_mutex_wound(struct MUTEX *lock, * it's wounded in __ww_mutex_check_kill() or has a * wakeup pending to re-read the wounded state. */ - if (owner != current) + if (owner != current) { + /* + * When waking up the task to wound, be sure to clear the + * blocked_on pointer. Otherwise we can see circular + * blocked_on relationships that can't resolve. + */ + __clear_task_blocked_on(owner, lock); wake_q_add(wake_q, owner); - + } return true; } |