1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Runtime locking correctness validator
5 * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
6 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
8 * see Documentation/locking/lockdep-design.txt for more details.
10 #ifndef __LINUX_LOCKDEP_H
11 #define __LINUX_LOCKDEP_H
17 extern int prove_locking;
20 #define MAX_LOCKDEP_SUBCLASSES 8UL
22 #include <linux/types.h>
26 #include <linux/linkage.h>
27 #include <linux/list.h>
28 #include <linux/debug_locks.h>
29 #include <linux/stacktrace.h>
32 * We'd rather not expose kernel/lockdep_states.h this wide, but we do need
33 * the total number of states... :-(
35 #define XXX_LOCK_USAGE_STATES (1+2*4)
38 * NR_LOCKDEP_CACHING_CLASSES ... Number of classes
39 * cached in the instance of lockdep_map
41 * Currently main class (subclass == 0) and signle depth subclass
42 * are cached in lockdep_map. This optimization is mainly targeting
43 * on rq->lock. double_rq_lock() acquires this highly competitive with
46 #define NR_LOCKDEP_CACHING_CLASSES 2
49 * A lockdep key is associated with each lock object. For static locks we use
50 * the lock address itself as the key. Dynamically allocated lock objects can
51 * have a statically or dynamically allocated key. Dynamically allocated lock
52 * keys must be registered before being used and must be unregistered before
53 * the key memory is freed.
55 struct lockdep_subclass_key {
57 } __attribute__ ((__packed__));
59 /* hash_entry is used to keep track of dynamically allocated keys. */
60 struct lock_class_key {
62 struct hlist_node hash_entry;
63 struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES];
67 extern struct lock_class_key __lockdep_no_validate__;
69 #define LOCKSTAT_POINTS 4
72 * The lock-class itself. The order of the structure members matters.
73 * reinit_class() zeroes the key member and all subsequent members.
79 struct hlist_node hash_entry;
82 * Entry in all_lock_classes when in use. Entry in free_lock_classes
83 * when not in use. Instances that are being freed are on one of the
84 * zapped_classes lists.
86 struct list_head lock_entry;
89 * These fields represent a directed graph of lock dependencies,
90 * to every node we attach a list of "forward" and a list of
91 * "backward" graph nodes.
93 struct list_head locks_after, locks_before;
95 struct lockdep_subclass_key *key;
96 unsigned int subclass;
97 unsigned int dep_gen_id;
100 * IRQ/softirq usage tracking bits:
102 unsigned long usage_mask;
103 struct stack_trace usage_traces[XXX_LOCK_USAGE_STATES];
106 * Generation counter, when doing certain classes of graph walking,
107 * to ensure that we check one node only once:
112 #ifdef CONFIG_LOCK_STAT
113 unsigned long contention_point[LOCKSTAT_POINTS];
114 unsigned long contending_point[LOCKSTAT_POINTS];
116 } __no_randomize_layout;
118 #ifdef CONFIG_LOCK_STAT
127 bounce_acquired_write,
128 bounce_acquired_read,
129 bounce_contended_write,
130 bounce_contended_read,
133 bounce_acquired = bounce_acquired_write,
134 bounce_contended = bounce_contended_write,
137 struct lock_class_stats {
138 unsigned long contention_point[LOCKSTAT_POINTS];
139 unsigned long contending_point[LOCKSTAT_POINTS];
140 struct lock_time read_waittime;
141 struct lock_time write_waittime;
142 struct lock_time read_holdtime;
143 struct lock_time write_holdtime;
144 unsigned long bounces[nr_bounce_types];
147 struct lock_class_stats lock_stats(struct lock_class *class);
148 void clear_lock_stats(struct lock_class *class);
152 * Map the lock object (the lock instance) to the lock-class object.
153 * This is embedded into specific lock instances:
156 struct lock_class_key *key;
157 struct lock_class *class_cache[NR_LOCKDEP_CACHING_CLASSES];
159 #ifdef CONFIG_LOCK_STAT
165 static inline void lockdep_copy_map(struct lockdep_map *to,
166 struct lockdep_map *from)
172 * Since the class cache can be modified concurrently we could observe
173 * half pointers (64bit arch using 32bit copy insns). Therefore clear
174 * the caches and take the performance hit.
176 * XXX it doesn't work well with lockdep_set_class_and_subclass(), since
177 * that relies on cache abuse.
179 for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
180 to->class_cache[i] = NULL;
184 * Every lock has a list of other locks that were taken after it.
185 * We only grow the list, never remove from it:
188 struct list_head entry;
189 struct lock_class *class;
190 struct lock_class *links_to;
191 struct stack_trace trace;
195 * The parent field is used to implement breadth-first search, and the
196 * bit 0 is reused to indicate if the lock has been accessed in BFS.
198 struct lock_list *parent;
202 * We record lock dependency chains, so that we can cache them:
205 /* see BUILD_BUG_ON()s in lookup_chain_cache() */
206 unsigned int irq_context : 2,
210 struct hlist_node entry;
214 #define MAX_LOCKDEP_KEYS_BITS 13
216 * Subtract one because we offset hlock->class_idx by 1 in order
217 * to make 0 mean no class. This avoids overflowing the class_idx
218 * bitfield and hitting the BUG in hlock_class().
220 #define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1)
224 * One-way hash of the dependency chain up to this point. We
225 * hash the hashes step by step as the dependency chain grows.
227 * We use it for dependency-caching and we skip detection
228 * passes and dependency-updates if there is a cache-hit, so
229 * it is absolutely critical for 100% coverage of the validator
230 * to have a unique key value for every unique dependency path
231 * that can occur in the system, to make a unique hash value
232 * as likely as possible - hence the 64-bit width.
234 * The task struct holds the current hash value (initialized
235 * with zero), here we store the previous hash value:
238 unsigned long acquire_ip;
239 struct lockdep_map *instance;
240 struct lockdep_map *nest_lock;
241 #ifdef CONFIG_LOCK_STAT
245 unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS;
247 * The lock-stack is unified in that the lock chains of interrupt
248 * contexts nest ontop of process context chains, but we 'separate'
249 * the hashes by starting with 0 if we cross into an interrupt
250 * context, and we also keep do not add cross-context lock
251 * dependencies - the lock usage graph walking covers that area
252 * anyway, and we'd just unnecessarily increase the number of
253 * dependencies otherwise. [Note: hardirq and softirq contexts
254 * are separated from each other too.]
256 * The following field is used to detect when we cross into an
259 unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */
260 unsigned int trylock:1; /* 16 bits */
262 unsigned int read:2; /* see lock_acquire() comment */
263 unsigned int check:1; /* see lock_acquire() comment */
264 unsigned int hardirqs_off:1;
265 unsigned int references:12; /* 32 bits */
266 unsigned int pin_count;
270 * Initialization, self-test and debugging-output methods:
272 extern void lockdep_init(void);
273 extern void lockdep_reset(void);
274 extern void lockdep_reset_lock(struct lockdep_map *lock);
275 extern void lockdep_free_key_range(void *start, unsigned long size);
276 extern asmlinkage void lockdep_sys_exit(void);
277 extern void lockdep_set_selftest_task(struct task_struct *task);
279 extern void lockdep_off(void);
280 extern void lockdep_on(void);
282 extern void lockdep_register_key(struct lock_class_key *key);
283 extern void lockdep_unregister_key(struct lock_class_key *key);
286 * These methods are used by specific locking variants (spinlocks,
287 * rwlocks, mutexes and rwsems) to pass init/acquire/release events
291 extern void lockdep_init_map(struct lockdep_map *lock, const char *name,
292 struct lock_class_key *key, int subclass);
295 * Reinitialize a lock key - for cases where there is special locking or
296 * special initialization of locks so that the validator gets the scope
297 * of dependencies wrong: they are either too broad (they need a class-split)
298 * or they are too narrow (they suffer from a false class-split):
300 #define lockdep_set_class(lock, key) \
301 lockdep_init_map(&(lock)->dep_map, #key, key, 0)
302 #define lockdep_set_class_and_name(lock, key, name) \
303 lockdep_init_map(&(lock)->dep_map, name, key, 0)
304 #define lockdep_set_class_and_subclass(lock, key, sub) \
305 lockdep_init_map(&(lock)->dep_map, #key, key, sub)
306 #define lockdep_set_subclass(lock, sub) \
307 lockdep_init_map(&(lock)->dep_map, #lock, \
308 (lock)->dep_map.key, sub)
310 #define lockdep_set_novalidate_class(lock) \
311 lockdep_set_class_and_name(lock, &__lockdep_no_validate__, #lock)
313 * Compare locking classes
315 #define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key)
317 static inline int lockdep_match_key(struct lockdep_map *lock,
318 struct lock_class_key *key)
320 return lock->key == key;
328 * 0: exclusive (write) acquire
329 * 1: read-acquire (no recursion allowed)
330 * 2: read-acquire with same-instance recursion allowed
334 * 0: simple checks (freeing, held-at-exit-time, etc.)
337 extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
338 int trylock, int read, int check,
339 struct lockdep_map *nest_lock, unsigned long ip);
341 extern void lock_release(struct lockdep_map *lock, int nested,
345 * Same "read" as for lock_acquire(), except -1 means any.
347 extern int lock_is_held_type(const struct lockdep_map *lock, int read);
349 static inline int lock_is_held(const struct lockdep_map *lock)
351 return lock_is_held_type(lock, -1);
354 #define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map)
355 #define lockdep_is_held_type(lock, r) lock_is_held_type(&(lock)->dep_map, (r))
357 extern void lock_set_class(struct lockdep_map *lock, const char *name,
358 struct lock_class_key *key, unsigned int subclass,
361 static inline void lock_set_subclass(struct lockdep_map *lock,
362 unsigned int subclass, unsigned long ip)
364 lock_set_class(lock, lock->name, lock->key, subclass, ip);
367 extern void lock_downgrade(struct lockdep_map *lock, unsigned long ip);
369 struct pin_cookie { unsigned int val; };
371 #define NIL_COOKIE (struct pin_cookie){ .val = 0U, }
373 extern struct pin_cookie lock_pin_lock(struct lockdep_map *lock);
374 extern void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie);
375 extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie);
377 #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
379 #define lockdep_assert_held(l) do { \
380 WARN_ON(debug_locks && !lockdep_is_held(l)); \
383 #define lockdep_assert_held_exclusive(l) do { \
384 WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \
387 #define lockdep_assert_held_read(l) do { \
388 WARN_ON(debug_locks && !lockdep_is_held_type(l, 1)); \
391 #define lockdep_assert_held_once(l) do { \
392 WARN_ON_ONCE(debug_locks && !lockdep_is_held(l)); \
395 #define lockdep_recursing(tsk) ((tsk)->lockdep_recursion)
397 #define lockdep_pin_lock(l) lock_pin_lock(&(l)->dep_map)
398 #define lockdep_repin_lock(l,c) lock_repin_lock(&(l)->dep_map, (c))
399 #define lockdep_unpin_lock(l,c) lock_unpin_lock(&(l)->dep_map, (c))
401 #else /* !CONFIG_LOCKDEP */
403 static inline void lockdep_off(void)
407 static inline void lockdep_on(void)
411 static inline void lockdep_set_selftest_task(struct task_struct *task)
415 # define lock_acquire(l, s, t, r, c, n, i) do { } while (0)
416 # define lock_release(l, n, i) do { } while (0)
417 # define lock_downgrade(l, i) do { } while (0)
418 # define lock_set_class(l, n, k, s, i) do { } while (0)
419 # define lock_set_subclass(l, s, i) do { } while (0)
420 # define lockdep_init() do { } while (0)
421 # define lockdep_init_map(lock, name, key, sub) \
422 do { (void)(name); (void)(key); } while (0)
423 # define lockdep_set_class(lock, key) do { (void)(key); } while (0)
424 # define lockdep_set_class_and_name(lock, key, name) \
425 do { (void)(key); (void)(name); } while (0)
426 #define lockdep_set_class_and_subclass(lock, key, sub) \
427 do { (void)(key); } while (0)
428 #define lockdep_set_subclass(lock, sub) do { } while (0)
430 #define lockdep_set_novalidate_class(lock) do { } while (0)
433 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
434 * case since the result is not well defined and the caller should rather
435 * #ifdef the call himself.
438 # define lockdep_reset() do { debug_locks = 1; } while (0)
439 # define lockdep_free_key_range(start, size) do { } while (0)
440 # define lockdep_sys_exit() do { } while (0)
442 * The class key takes no space if lockdep is disabled:
444 struct lock_class_key { };
446 static inline void lockdep_register_key(struct lock_class_key *key)
450 static inline void lockdep_unregister_key(struct lock_class_key *key)
455 * The lockdep_map takes no space if lockdep is disabled:
457 struct lockdep_map { };
459 #define lockdep_depth(tsk) (0)
461 #define lockdep_is_held_type(l, r) (1)
463 #define lockdep_assert_held(l) do { (void)(l); } while (0)
464 #define lockdep_assert_held_exclusive(l) do { (void)(l); } while (0)
465 #define lockdep_assert_held_read(l) do { (void)(l); } while (0)
466 #define lockdep_assert_held_once(l) do { (void)(l); } while (0)
468 #define lockdep_recursing(tsk) (0)
470 struct pin_cookie { };
472 #define NIL_COOKIE (struct pin_cookie){ }
474 #define lockdep_pin_lock(l) ({ struct pin_cookie cookie; cookie; })
475 #define lockdep_repin_lock(l, c) do { (void)(l); (void)(c); } while (0)
476 #define lockdep_unpin_lock(l, c) do { (void)(l); (void)(c); } while (0)
478 #endif /* !LOCKDEP */
480 enum xhlock_context_t {
486 #define lockdep_init_map_crosslock(m, n, k, s) do {} while (0)
488 * To initialize a lockdep_map statically use this macro.
489 * Note that _name must not be NULL.
491 #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
492 { .name = (_name), .key = (void *)(_key), }
494 static inline void lockdep_invariant_state(bool force) {}
495 static inline void lockdep_init_task(struct task_struct *task) {}
496 static inline void lockdep_free_task(struct task_struct *task) {}
498 #ifdef CONFIG_LOCK_STAT
500 extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
501 extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);
503 #define LOCK_CONTENDED(_lock, try, lock) \
506 lock_contended(&(_lock)->dep_map, _RET_IP_); \
509 lock_acquired(&(_lock)->dep_map, _RET_IP_); \
512 #define LOCK_CONTENDED_RETURN(_lock, try, lock) \
516 lock_contended(&(_lock)->dep_map, _RET_IP_); \
517 ____err = lock(_lock); \
520 lock_acquired(&(_lock)->dep_map, _RET_IP_); \
524 #else /* CONFIG_LOCK_STAT */
526 #define lock_contended(lockdep_map, ip) do {} while (0)
527 #define lock_acquired(lockdep_map, ip) do {} while (0)
529 #define LOCK_CONTENDED(_lock, try, lock) \
532 #define LOCK_CONTENDED_RETURN(_lock, try, lock) \
535 #endif /* CONFIG_LOCK_STAT */
537 #ifdef CONFIG_LOCKDEP
540 * On lockdep we dont want the hand-coded irq-enable of
541 * _raw_*_lock_flags() code, because lockdep assumes
542 * that interrupts are not re-enabled during lock-acquire:
544 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
545 LOCK_CONTENDED((_lock), (try), (lock))
547 #else /* CONFIG_LOCKDEP */
549 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
550 lockfl((_lock), (flags))
552 #endif /* CONFIG_LOCKDEP */
554 #ifdef CONFIG_PROVE_LOCKING
555 extern void print_irqtrace_events(struct task_struct *curr);
557 static inline void print_irqtrace_events(struct task_struct *curr)
563 * For trivial one-depth nesting of a lock-class, the following
564 * global define can be used. (Subsystems with multiple levels
565 * of nesting should define their own lock-nesting subclasses.)
567 #define SINGLE_DEPTH_NESTING 1
570 * Map the dependency ops to NOP or to real lockdep ops, depending
571 * on the per lock-class debug mode:
574 #define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i)
575 #define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i)
576 #define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i)
578 #define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
579 #define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
580 #define spin_release(l, n, i) lock_release(l, n, i)
582 #define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
583 #define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i)
584 #define rwlock_release(l, n, i) lock_release(l, n, i)
586 #define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
587 #define seqcount_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i)
588 #define seqcount_release(l, n, i) lock_release(l, n, i)
590 #define mutex_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
591 #define mutex_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
592 #define mutex_release(l, n, i) lock_release(l, n, i)
594 #define rwsem_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
595 #define rwsem_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
596 #define rwsem_acquire_read(l, s, t, i) lock_acquire_shared(l, s, t, NULL, i)
597 #define rwsem_release(l, n, i) lock_release(l, n, i)
599 #define lock_map_acquire(l) lock_acquire_exclusive(l, 0, 0, NULL, _THIS_IP_)
600 #define lock_map_acquire_read(l) lock_acquire_shared_recursive(l, 0, 0, NULL, _THIS_IP_)
601 #define lock_map_acquire_tryread(l) lock_acquire_shared_recursive(l, 0, 1, NULL, _THIS_IP_)
602 #define lock_map_release(l) lock_release(l, 1, _THIS_IP_)
604 #ifdef CONFIG_PROVE_LOCKING
605 # define might_lock(lock) \
607 typecheck(struct lockdep_map *, &(lock)->dep_map); \
608 lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_); \
609 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
611 # define might_lock_read(lock) \
613 typecheck(struct lockdep_map *, &(lock)->dep_map); \
614 lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_); \
615 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
618 #define lockdep_assert_irqs_enabled() do { \
619 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
620 !current->hardirqs_enabled, \
621 "IRQs not enabled as expected\n"); \
624 #define lockdep_assert_irqs_disabled() do { \
625 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
626 current->hardirqs_enabled, \
627 "IRQs not disabled as expected\n"); \
631 # define might_lock(lock) do { } while (0)
632 # define might_lock_read(lock) do { } while (0)
633 # define lockdep_assert_irqs_enabled() do { } while (0)
634 # define lockdep_assert_irqs_disabled() do { } while (0)
637 #ifdef CONFIG_LOCKDEP
638 void lockdep_rcu_suspicious(const char *file, const int line, const char *s);
641 lockdep_rcu_suspicious(const char *file, const int line, const char *s)
646 #endif /* __LINUX_LOCKDEP_H */