1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Runtime locking correctness validator
6 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
8 * see Documentation/locking/lockdep-design.rst 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__;
71 #define LOCKSTAT_POINTS 4
74 * The lock-class itself. The order of the structure members matters.
75 * reinit_class() zeroes the key member and all subsequent members.
81 struct hlist_node hash_entry;
84 * Entry in all_lock_classes when in use. Entry in free_lock_classes
85 * when not in use. Instances that are being freed are on one of the
86 * zapped_classes lists.
88 struct list_head lock_entry;
91 * These fields represent a directed graph of lock dependencies,
92 * to every node we attach a list of "forward" and a list of
93 * "backward" graph nodes.
95 struct list_head locks_after, locks_before;
97 const struct lockdep_subclass_key *key;
98 unsigned int subclass;
99 unsigned int dep_gen_id;
102 * IRQ/softirq usage tracking bits:
104 unsigned long usage_mask;
105 const struct lock_trace *usage_traces[XXX_LOCK_USAGE_STATES];
108 * Generation counter, when doing certain classes of graph walking,
109 * to ensure that we check one node only once:
114 #ifdef CONFIG_LOCK_STAT
115 unsigned long contention_point[LOCKSTAT_POINTS];
116 unsigned long contending_point[LOCKSTAT_POINTS];
118 } __no_randomize_layout;
120 #ifdef CONFIG_LOCK_STAT
129 bounce_acquired_write,
130 bounce_acquired_read,
131 bounce_contended_write,
132 bounce_contended_read,
135 bounce_acquired = bounce_acquired_write,
136 bounce_contended = bounce_contended_write,
139 struct lock_class_stats {
140 unsigned long contention_point[LOCKSTAT_POINTS];
141 unsigned long contending_point[LOCKSTAT_POINTS];
142 struct lock_time read_waittime;
143 struct lock_time write_waittime;
144 struct lock_time read_holdtime;
145 struct lock_time write_holdtime;
146 unsigned long bounces[nr_bounce_types];
149 struct lock_class_stats lock_stats(struct lock_class *class);
150 void clear_lock_stats(struct lock_class *class);
154 * Map the lock object (the lock instance) to the lock-class object.
155 * This is embedded into specific lock instances:
158 struct lock_class_key *key;
159 struct lock_class *class_cache[NR_LOCKDEP_CACHING_CLASSES];
161 #ifdef CONFIG_LOCK_STAT
167 static inline void lockdep_copy_map(struct lockdep_map *to,
168 struct lockdep_map *from)
174 * Since the class cache can be modified concurrently we could observe
175 * half pointers (64bit arch using 32bit copy insns). Therefore clear
176 * the caches and take the performance hit.
178 * XXX it doesn't work well with lockdep_set_class_and_subclass(), since
179 * that relies on cache abuse.
181 for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
182 to->class_cache[i] = NULL;
186 * Every lock has a list of other locks that were taken after it.
187 * We only grow the list, never remove from it:
190 struct list_head entry;
191 struct lock_class *class;
192 struct lock_class *links_to;
193 const struct lock_trace *trace;
197 * The parent field is used to implement breadth-first search, and the
198 * bit 0 is reused to indicate if the lock has been accessed in BFS.
200 struct lock_list *parent;
204 * struct lock_chain - lock dependency chain record
206 * @irq_context: the same as irq_context in held_lock below
207 * @depth: the number of held locks in this chain
208 * @base: the index in chain_hlocks for this chain
209 * @entry: the collided lock chains in lock_chain hash list
210 * @chain_key: the hash key of this lock_chain
213 /* see BUILD_BUG_ON()s in add_chain_cache() */
214 unsigned int irq_context : 2,
218 struct hlist_node entry;
222 #define MAX_LOCKDEP_KEYS_BITS 13
223 #define MAX_LOCKDEP_KEYS (1UL << MAX_LOCKDEP_KEYS_BITS)
224 #define INITIAL_CHAIN_KEY -1
228 * One-way hash of the dependency chain up to this point. We
229 * hash the hashes step by step as the dependency chain grows.
231 * We use it for dependency-caching and we skip detection
232 * passes and dependency-updates if there is a cache-hit, so
233 * it is absolutely critical for 100% coverage of the validator
234 * to have a unique key value for every unique dependency path
235 * that can occur in the system, to make a unique hash value
236 * as likely as possible - hence the 64-bit width.
238 * The task struct holds the current hash value (initialized
239 * with zero), here we store the previous hash value:
242 unsigned long acquire_ip;
243 struct lockdep_map *instance;
244 struct lockdep_map *nest_lock;
245 #ifdef CONFIG_LOCK_STAT
250 * class_idx is zero-indexed; it points to the element in
251 * lock_classes this held lock instance belongs to. class_idx is in
252 * the range from 0 to (MAX_LOCKDEP_KEYS-1) inclusive.
254 unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS;
256 * The lock-stack is unified in that the lock chains of interrupt
257 * contexts nest ontop of process context chains, but we 'separate'
258 * the hashes by starting with 0 if we cross into an interrupt
259 * context, and we also keep do not add cross-context lock
260 * dependencies - the lock usage graph walking covers that area
261 * anyway, and we'd just unnecessarily increase the number of
262 * dependencies otherwise. [Note: hardirq and softirq contexts
263 * are separated from each other too.]
265 * The following field is used to detect when we cross into an
268 unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */
269 unsigned int trylock:1; /* 16 bits */
271 unsigned int read:2; /* see lock_acquire() comment */
272 unsigned int check:1; /* see lock_acquire() comment */
273 unsigned int hardirqs_off:1;
274 unsigned int references:12; /* 32 bits */
275 unsigned int pin_count;
279 * Initialization, self-test and debugging-output methods:
281 extern void lockdep_init(void);
282 extern void lockdep_reset(void);
283 extern void lockdep_reset_lock(struct lockdep_map *lock);
284 extern void lockdep_free_key_range(void *start, unsigned long size);
285 extern asmlinkage void lockdep_sys_exit(void);
286 extern void lockdep_set_selftest_task(struct task_struct *task);
288 extern void lockdep_init_task(struct task_struct *task);
290 extern void lockdep_off(void);
291 extern void lockdep_on(void);
293 extern void lockdep_register_key(struct lock_class_key *key);
294 extern void lockdep_unregister_key(struct lock_class_key *key);
297 * These methods are used by specific locking variants (spinlocks,
298 * rwlocks, mutexes and rwsems) to pass init/acquire/release events
302 extern void lockdep_init_map(struct lockdep_map *lock, const char *name,
303 struct lock_class_key *key, int subclass);
306 * Reinitialize a lock key - for cases where there is special locking or
307 * special initialization of locks so that the validator gets the scope
308 * of dependencies wrong: they are either too broad (they need a class-split)
309 * or they are too narrow (they suffer from a false class-split):
311 #define lockdep_set_class(lock, key) \
312 lockdep_init_map(&(lock)->dep_map, #key, key, 0)
313 #define lockdep_set_class_and_name(lock, key, name) \
314 lockdep_init_map(&(lock)->dep_map, name, key, 0)
315 #define lockdep_set_class_and_subclass(lock, key, sub) \
316 lockdep_init_map(&(lock)->dep_map, #key, key, sub)
317 #define lockdep_set_subclass(lock, sub) \
318 lockdep_init_map(&(lock)->dep_map, #lock, \
319 (lock)->dep_map.key, sub)
321 #define lockdep_set_novalidate_class(lock) \
322 lockdep_set_class_and_name(lock, &__lockdep_no_validate__, #lock)
324 * Compare locking classes
326 #define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key)
328 static inline int lockdep_match_key(struct lockdep_map *lock,
329 struct lock_class_key *key)
331 return lock->key == key;
339 * 0: exclusive (write) acquire
340 * 1: read-acquire (no recursion allowed)
341 * 2: read-acquire with same-instance recursion allowed
345 * 0: simple checks (freeing, held-at-exit-time, etc.)
348 extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
349 int trylock, int read, int check,
350 struct lockdep_map *nest_lock, unsigned long ip);
352 extern void lock_release(struct lockdep_map *lock, unsigned long ip);
355 * Same "read" as for lock_acquire(), except -1 means any.
357 extern int lock_is_held_type(const struct lockdep_map *lock, int read);
359 static inline int lock_is_held(const struct lockdep_map *lock)
361 return lock_is_held_type(lock, -1);
364 #define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map)
365 #define lockdep_is_held_type(lock, r) lock_is_held_type(&(lock)->dep_map, (r))
367 extern void lock_set_class(struct lockdep_map *lock, const char *name,
368 struct lock_class_key *key, unsigned int subclass,
371 static inline void lock_set_subclass(struct lockdep_map *lock,
372 unsigned int subclass, unsigned long ip)
374 lock_set_class(lock, lock->name, lock->key, subclass, ip);
377 extern void lock_downgrade(struct lockdep_map *lock, unsigned long ip);
379 struct pin_cookie { unsigned int val; };
381 #define NIL_COOKIE (struct pin_cookie){ .val = 0U, }
383 extern struct pin_cookie lock_pin_lock(struct lockdep_map *lock);
384 extern void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie);
385 extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie);
387 #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
389 #define lockdep_assert_held(l) do { \
390 WARN_ON(debug_locks && !lockdep_is_held(l)); \
393 #define lockdep_assert_held_write(l) do { \
394 WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \
397 #define lockdep_assert_held_read(l) do { \
398 WARN_ON(debug_locks && !lockdep_is_held_type(l, 1)); \
401 #define lockdep_assert_held_once(l) do { \
402 WARN_ON_ONCE(debug_locks && !lockdep_is_held(l)); \
405 #define lockdep_recursing(tsk) ((tsk)->lockdep_recursion)
407 #define lockdep_pin_lock(l) lock_pin_lock(&(l)->dep_map)
408 #define lockdep_repin_lock(l,c) lock_repin_lock(&(l)->dep_map, (c))
409 #define lockdep_unpin_lock(l,c) lock_unpin_lock(&(l)->dep_map, (c))
411 #else /* !CONFIG_LOCKDEP */
413 static inline void lockdep_init_task(struct task_struct *task)
417 static inline void lockdep_off(void)
421 static inline void lockdep_on(void)
425 static inline void lockdep_set_selftest_task(struct task_struct *task)
429 # define lock_acquire(l, s, t, r, c, n, i) do { } while (0)
430 # define lock_release(l, i) do { } while (0)
431 # define lock_downgrade(l, i) do { } while (0)
432 # define lock_set_class(l, n, k, s, i) do { } while (0)
433 # define lock_set_subclass(l, s, i) do { } while (0)
434 # define lockdep_init() do { } while (0)
435 # define lockdep_init_map(lock, name, key, sub) \
436 do { (void)(name); (void)(key); } while (0)
437 # define lockdep_set_class(lock, key) do { (void)(key); } while (0)
438 # define lockdep_set_class_and_name(lock, key, name) \
439 do { (void)(key); (void)(name); } while (0)
440 #define lockdep_set_class_and_subclass(lock, key, sub) \
441 do { (void)(key); } while (0)
442 #define lockdep_set_subclass(lock, sub) do { } while (0)
444 #define lockdep_set_novalidate_class(lock) do { } while (0)
447 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
448 * case since the result is not well defined and the caller should rather
449 * #ifdef the call himself.
452 # define lockdep_reset() do { debug_locks = 1; } while (0)
453 # define lockdep_free_key_range(start, size) do { } while (0)
454 # define lockdep_sys_exit() do { } while (0)
456 * The class key takes no space if lockdep is disabled:
458 struct lock_class_key { };
460 static inline void lockdep_register_key(struct lock_class_key *key)
464 static inline void lockdep_unregister_key(struct lock_class_key *key)
469 * The lockdep_map takes no space if lockdep is disabled:
471 struct lockdep_map { };
473 #define lockdep_depth(tsk) (0)
475 #define lockdep_is_held_type(l, r) (1)
477 #define lockdep_assert_held(l) do { (void)(l); } while (0)
478 #define lockdep_assert_held_write(l) do { (void)(l); } while (0)
479 #define lockdep_assert_held_read(l) do { (void)(l); } while (0)
480 #define lockdep_assert_held_once(l) do { (void)(l); } while (0)
482 #define lockdep_recursing(tsk) (0)
484 struct pin_cookie { };
486 #define NIL_COOKIE (struct pin_cookie){ }
488 #define lockdep_pin_lock(l) ({ struct pin_cookie cookie = { }; cookie; })
489 #define lockdep_repin_lock(l, c) do { (void)(l); (void)(c); } while (0)
490 #define lockdep_unpin_lock(l, c) do { (void)(l); (void)(c); } while (0)
492 #endif /* !LOCKDEP */
494 enum xhlock_context_t {
500 #define lockdep_init_map_crosslock(m, n, k, s) do {} while (0)
502 * To initialize a lockdep_map statically use this macro.
503 * Note that _name must not be NULL.
505 #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
506 { .name = (_name), .key = (void *)(_key), }
508 static inline void lockdep_invariant_state(bool force) {}
509 static inline void lockdep_free_task(struct task_struct *task) {}
511 #ifdef CONFIG_LOCK_STAT
513 extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
514 extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);
516 #define LOCK_CONTENDED(_lock, try, lock) \
519 lock_contended(&(_lock)->dep_map, _RET_IP_); \
522 lock_acquired(&(_lock)->dep_map, _RET_IP_); \
525 #define LOCK_CONTENDED_RETURN(_lock, try, lock) \
529 lock_contended(&(_lock)->dep_map, _RET_IP_); \
530 ____err = lock(_lock); \
533 lock_acquired(&(_lock)->dep_map, _RET_IP_); \
537 #else /* CONFIG_LOCK_STAT */
539 #define lock_contended(lockdep_map, ip) do {} while (0)
540 #define lock_acquired(lockdep_map, ip) do {} while (0)
542 #define LOCK_CONTENDED(_lock, try, lock) \
545 #define LOCK_CONTENDED_RETURN(_lock, try, lock) \
548 #endif /* CONFIG_LOCK_STAT */
550 #ifdef CONFIG_LOCKDEP
553 * On lockdep we dont want the hand-coded irq-enable of
554 * _raw_*_lock_flags() code, because lockdep assumes
555 * that interrupts are not re-enabled during lock-acquire:
557 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
558 LOCK_CONTENDED((_lock), (try), (lock))
560 #else /* CONFIG_LOCKDEP */
562 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
563 lockfl((_lock), (flags))
565 #endif /* CONFIG_LOCKDEP */
567 #ifdef CONFIG_PROVE_LOCKING
568 extern void print_irqtrace_events(struct task_struct *curr);
570 static inline void print_irqtrace_events(struct task_struct *curr)
576 * For trivial one-depth nesting of a lock-class, the following
577 * global define can be used. (Subsystems with multiple levels
578 * of nesting should define their own lock-nesting subclasses.)
580 #define SINGLE_DEPTH_NESTING 1
583 * Map the dependency ops to NOP or to real lockdep ops, depending
584 * on the per lock-class debug mode:
587 #define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i)
588 #define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i)
589 #define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i)
591 #define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
592 #define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
593 #define spin_release(l, i) lock_release(l, i)
595 #define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
596 #define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i)
597 #define rwlock_release(l, i) lock_release(l, i)
599 #define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
600 #define seqcount_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i)
601 #define seqcount_release(l, i) lock_release(l, i)
603 #define mutex_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
604 #define mutex_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
605 #define mutex_release(l, i) lock_release(l, i)
607 #define rwsem_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
608 #define rwsem_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
609 #define rwsem_acquire_read(l, s, t, i) lock_acquire_shared(l, s, t, NULL, i)
610 #define rwsem_release(l, i) lock_release(l, i)
612 #define lock_map_acquire(l) lock_acquire_exclusive(l, 0, 0, NULL, _THIS_IP_)
613 #define lock_map_acquire_read(l) lock_acquire_shared_recursive(l, 0, 0, NULL, _THIS_IP_)
614 #define lock_map_acquire_tryread(l) lock_acquire_shared_recursive(l, 0, 1, NULL, _THIS_IP_)
615 #define lock_map_release(l) lock_release(l, _THIS_IP_)
617 #ifdef CONFIG_PROVE_LOCKING
618 # define might_lock(lock) \
620 typecheck(struct lockdep_map *, &(lock)->dep_map); \
621 lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_); \
622 lock_release(&(lock)->dep_map, _THIS_IP_); \
624 # define might_lock_read(lock) \
626 typecheck(struct lockdep_map *, &(lock)->dep_map); \
627 lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_); \
628 lock_release(&(lock)->dep_map, _THIS_IP_); \
631 #define lockdep_assert_irqs_enabled() do { \
632 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
633 !current->hardirqs_enabled, \
634 "IRQs not enabled as expected\n"); \
637 #define lockdep_assert_irqs_disabled() do { \
638 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
639 current->hardirqs_enabled, \
640 "IRQs not disabled as expected\n"); \
643 #define lockdep_assert_in_irq() do { \
644 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
645 !current->hardirq_context, \
646 "Not in hardirq as expected\n"); \
650 # define might_lock(lock) do { } while (0)
651 # define might_lock_read(lock) do { } while (0)
652 # define lockdep_assert_irqs_enabled() do { } while (0)
653 # define lockdep_assert_irqs_disabled() do { } while (0)
654 # define lockdep_assert_in_irq() do { } while (0)
657 #ifdef CONFIG_LOCKDEP
658 void lockdep_rcu_suspicious(const char *file, const int line, const char *s);
661 lockdep_rcu_suspicious(const char *file, const int line, const char *s)
666 #endif /* __LINUX_LOCKDEP_H */