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.rst for more details.
10 #ifndef __LINUX_LOCKDEP_H
11 #define __LINUX_LOCKDEP_H
13 #include <linux/lockdep_types.h>
14 #include <linux/smp.h>
15 #include <asm/percpu.h>
20 extern int prove_locking;
25 #include <linux/linkage.h>
26 #include <linux/list.h>
27 #include <linux/debug_locks.h>
28 #include <linux/stacktrace.h>
30 static inline void lockdep_copy_map(struct lockdep_map *to,
31 struct lockdep_map *from)
37 * Since the class cache can be modified concurrently we could observe
38 * half pointers (64bit arch using 32bit copy insns). Therefore clear
39 * the caches and take the performance hit.
41 * XXX it doesn't work well with lockdep_set_class_and_subclass(), since
42 * that relies on cache abuse.
44 for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
45 to->class_cache[i] = NULL;
49 * Every lock has a list of other locks that were taken after it.
50 * We only grow the list, never remove from it:
53 struct list_head entry;
54 struct lock_class *class;
55 struct lock_class *links_to;
56 const struct lock_trace *trace;
58 /* bitmap of different dependencies from head to this */
60 /* used by BFS to record whether "prev -> this" only has -(*R)-> */
64 * The parent field is used to implement breadth-first search, and the
65 * bit 0 is reused to indicate if the lock has been accessed in BFS.
67 struct lock_list *parent;
71 * struct lock_chain - lock dependency chain record
73 * @irq_context: the same as irq_context in held_lock below
74 * @depth: the number of held locks in this chain
75 * @base: the index in chain_hlocks for this chain
76 * @entry: the collided lock chains in lock_chain hash list
77 * @chain_key: the hash key of this lock_chain
80 /* see BUILD_BUG_ON()s in add_chain_cache() */
81 unsigned int irq_context : 2,
85 struct hlist_node entry;
89 #define MAX_LOCKDEP_KEYS_BITS 13
90 #define MAX_LOCKDEP_KEYS (1UL << MAX_LOCKDEP_KEYS_BITS)
91 #define INITIAL_CHAIN_KEY -1
95 * One-way hash of the dependency chain up to this point. We
96 * hash the hashes step by step as the dependency chain grows.
98 * We use it for dependency-caching and we skip detection
99 * passes and dependency-updates if there is a cache-hit, so
100 * it is absolutely critical for 100% coverage of the validator
101 * to have a unique key value for every unique dependency path
102 * that can occur in the system, to make a unique hash value
103 * as likely as possible - hence the 64-bit width.
105 * The task struct holds the current hash value (initialized
106 * with zero), here we store the previous hash value:
109 unsigned long acquire_ip;
110 struct lockdep_map *instance;
111 struct lockdep_map *nest_lock;
112 #ifdef CONFIG_LOCK_STAT
117 * class_idx is zero-indexed; it points to the element in
118 * lock_classes this held lock instance belongs to. class_idx is in
119 * the range from 0 to (MAX_LOCKDEP_KEYS-1) inclusive.
121 unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS;
123 * The lock-stack is unified in that the lock chains of interrupt
124 * contexts nest ontop of process context chains, but we 'separate'
125 * the hashes by starting with 0 if we cross into an interrupt
126 * context, and we also keep do not add cross-context lock
127 * dependencies - the lock usage graph walking covers that area
128 * anyway, and we'd just unnecessarily increase the number of
129 * dependencies otherwise. [Note: hardirq and softirq contexts
130 * are separated from each other too.]
132 * The following field is used to detect when we cross into an
135 unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */
136 unsigned int trylock:1; /* 16 bits */
138 unsigned int read:2; /* see lock_acquire() comment */
139 unsigned int check:1; /* see lock_acquire() comment */
140 unsigned int hardirqs_off:1;
141 unsigned int references:12; /* 32 bits */
142 unsigned int pin_count;
146 * Initialization, self-test and debugging-output methods:
148 extern void lockdep_init(void);
149 extern void lockdep_reset(void);
150 extern void lockdep_reset_lock(struct lockdep_map *lock);
151 extern void lockdep_free_key_range(void *start, unsigned long size);
152 extern asmlinkage void lockdep_sys_exit(void);
153 extern void lockdep_set_selftest_task(struct task_struct *task);
155 extern void lockdep_init_task(struct task_struct *task);
158 * Split the recrursion counter in two to readily detect 'off' vs recursion.
160 #define LOCKDEP_RECURSION_BITS 16
161 #define LOCKDEP_OFF (1U << LOCKDEP_RECURSION_BITS)
162 #define LOCKDEP_RECURSION_MASK (LOCKDEP_OFF - 1)
165 * lockdep_{off,on}() are macros to avoid tracing and kprobes; not inlines due
166 * to header dependencies.
169 #define lockdep_off() \
171 current->lockdep_recursion += LOCKDEP_OFF; \
174 #define lockdep_on() \
176 current->lockdep_recursion -= LOCKDEP_OFF; \
179 extern void lockdep_register_key(struct lock_class_key *key);
180 extern void lockdep_unregister_key(struct lock_class_key *key);
183 * These methods are used by specific locking variants (spinlocks,
184 * rwlocks, mutexes and rwsems) to pass init/acquire/release events
188 extern void lockdep_init_map_type(struct lockdep_map *lock, const char *name,
189 struct lock_class_key *key, int subclass, u8 inner, u8 outer, u8 lock_type);
192 lockdep_init_map_waits(struct lockdep_map *lock, const char *name,
193 struct lock_class_key *key, int subclass, u8 inner, u8 outer)
195 lockdep_init_map_type(lock, name, key, subclass, inner, LD_WAIT_INV, LD_LOCK_NORMAL);
199 lockdep_init_map_wait(struct lockdep_map *lock, const char *name,
200 struct lock_class_key *key, int subclass, u8 inner)
202 lockdep_init_map_waits(lock, name, key, subclass, inner, LD_WAIT_INV);
205 static inline void lockdep_init_map(struct lockdep_map *lock, const char *name,
206 struct lock_class_key *key, int subclass)
208 lockdep_init_map_wait(lock, name, key, subclass, LD_WAIT_INV);
212 * Reinitialize a lock key - for cases where there is special locking or
213 * special initialization of locks so that the validator gets the scope
214 * of dependencies wrong: they are either too broad (they need a class-split)
215 * or they are too narrow (they suffer from a false class-split):
217 #define lockdep_set_class(lock, key) \
218 lockdep_init_map_waits(&(lock)->dep_map, #key, key, 0, \
219 (lock)->dep_map.wait_type_inner, \
220 (lock)->dep_map.wait_type_outer)
222 #define lockdep_set_class_and_name(lock, key, name) \
223 lockdep_init_map_waits(&(lock)->dep_map, name, key, 0, \
224 (lock)->dep_map.wait_type_inner, \
225 (lock)->dep_map.wait_type_outer)
227 #define lockdep_set_class_and_subclass(lock, key, sub) \
228 lockdep_init_map_waits(&(lock)->dep_map, #key, key, sub,\
229 (lock)->dep_map.wait_type_inner, \
230 (lock)->dep_map.wait_type_outer)
232 #define lockdep_set_subclass(lock, sub) \
233 lockdep_init_map_waits(&(lock)->dep_map, #lock, (lock)->dep_map.key, sub,\
234 (lock)->dep_map.wait_type_inner, \
235 (lock)->dep_map.wait_type_outer)
237 #define lockdep_set_novalidate_class(lock) \
238 lockdep_set_class_and_name(lock, &__lockdep_no_validate__, #lock)
241 * Compare locking classes
243 #define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key)
245 static inline int lockdep_match_key(struct lockdep_map *lock,
246 struct lock_class_key *key)
248 return lock->key == key;
256 * 0: exclusive (write) acquire
257 * 1: read-acquire (no recursion allowed)
258 * 2: read-acquire with same-instance recursion allowed
262 * 0: simple checks (freeing, held-at-exit-time, etc.)
265 extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
266 int trylock, int read, int check,
267 struct lockdep_map *nest_lock, unsigned long ip);
269 extern void lock_release(struct lockdep_map *lock, unsigned long ip);
272 * Same "read" as for lock_acquire(), except -1 means any.
274 extern int lock_is_held_type(const struct lockdep_map *lock, int read);
276 static inline int lock_is_held(const struct lockdep_map *lock)
278 return lock_is_held_type(lock, -1);
281 #define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map)
282 #define lockdep_is_held_type(lock, r) lock_is_held_type(&(lock)->dep_map, (r))
284 extern void lock_set_class(struct lockdep_map *lock, const char *name,
285 struct lock_class_key *key, unsigned int subclass,
288 static inline void lock_set_subclass(struct lockdep_map *lock,
289 unsigned int subclass, unsigned long ip)
291 lock_set_class(lock, lock->name, lock->key, subclass, ip);
294 extern void lock_downgrade(struct lockdep_map *lock, unsigned long ip);
296 #define NIL_COOKIE (struct pin_cookie){ .val = 0U, }
298 extern struct pin_cookie lock_pin_lock(struct lockdep_map *lock);
299 extern void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie);
300 extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie);
302 #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
304 #define lockdep_assert_held(l) do { \
305 WARN_ON(debug_locks && !lockdep_is_held(l)); \
308 #define lockdep_assert_held_write(l) do { \
309 WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \
312 #define lockdep_assert_held_read(l) do { \
313 WARN_ON(debug_locks && !lockdep_is_held_type(l, 1)); \
316 #define lockdep_assert_held_once(l) do { \
317 WARN_ON_ONCE(debug_locks && !lockdep_is_held(l)); \
320 #define lockdep_recursing(tsk) ((tsk)->lockdep_recursion)
322 #define lockdep_pin_lock(l) lock_pin_lock(&(l)->dep_map)
323 #define lockdep_repin_lock(l,c) lock_repin_lock(&(l)->dep_map, (c))
324 #define lockdep_unpin_lock(l,c) lock_unpin_lock(&(l)->dep_map, (c))
326 #else /* !CONFIG_LOCKDEP */
328 static inline void lockdep_init_task(struct task_struct *task)
332 static inline void lockdep_off(void)
336 static inline void lockdep_on(void)
340 static inline void lockdep_set_selftest_task(struct task_struct *task)
344 # define lock_acquire(l, s, t, r, c, n, i) do { } while (0)
345 # define lock_release(l, i) do { } while (0)
346 # define lock_downgrade(l, i) do { } while (0)
347 # define lock_set_class(l, n, k, s, i) do { } while (0)
348 # define lock_set_subclass(l, s, i) do { } while (0)
349 # define lockdep_init() do { } while (0)
350 # define lockdep_init_map_type(lock, name, key, sub, inner, outer, type) \
351 do { (void)(name); (void)(key); } while (0)
352 # define lockdep_init_map_waits(lock, name, key, sub, inner, outer) \
353 do { (void)(name); (void)(key); } while (0)
354 # define lockdep_init_map_wait(lock, name, key, sub, inner) \
355 do { (void)(name); (void)(key); } while (0)
356 # define lockdep_init_map(lock, name, key, sub) \
357 do { (void)(name); (void)(key); } while (0)
358 # define lockdep_set_class(lock, key) do { (void)(key); } while (0)
359 # define lockdep_set_class_and_name(lock, key, name) \
360 do { (void)(key); (void)(name); } while (0)
361 #define lockdep_set_class_and_subclass(lock, key, sub) \
362 do { (void)(key); } while (0)
363 #define lockdep_set_subclass(lock, sub) do { } while (0)
365 #define lockdep_set_novalidate_class(lock) do { } while (0)
368 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
369 * case since the result is not well defined and the caller should rather
370 * #ifdef the call himself.
373 # define lockdep_reset() do { debug_locks = 1; } while (0)
374 # define lockdep_free_key_range(start, size) do { } while (0)
375 # define lockdep_sys_exit() do { } while (0)
377 static inline void lockdep_register_key(struct lock_class_key *key)
381 static inline void lockdep_unregister_key(struct lock_class_key *key)
385 #define lockdep_depth(tsk) (0)
388 * Dummy forward declarations, allow users to write less ifdef-y code
389 * and depend on dead code elimination.
391 extern int lock_is_held(const void *);
392 extern int lockdep_is_held(const void *);
393 #define lockdep_is_held_type(l, r) (1)
395 #define lockdep_assert_held(l) do { (void)(l); } while (0)
396 #define lockdep_assert_held_write(l) do { (void)(l); } while (0)
397 #define lockdep_assert_held_read(l) do { (void)(l); } while (0)
398 #define lockdep_assert_held_once(l) do { (void)(l); } while (0)
400 #define lockdep_recursing(tsk) (0)
402 #define NIL_COOKIE (struct pin_cookie){ }
404 #define lockdep_pin_lock(l) ({ struct pin_cookie cookie = { }; cookie; })
405 #define lockdep_repin_lock(l, c) do { (void)(l); (void)(c); } while (0)
406 #define lockdep_unpin_lock(l, c) do { (void)(l); (void)(c); } while (0)
408 #endif /* !LOCKDEP */
410 enum xhlock_context_t {
416 #define lockdep_init_map_crosslock(m, n, k, s) do {} while (0)
418 * To initialize a lockdep_map statically use this macro.
419 * Note that _name must not be NULL.
421 #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
422 { .name = (_name), .key = (void *)(_key), }
424 static inline void lockdep_invariant_state(bool force) {}
425 static inline void lockdep_free_task(struct task_struct *task) {}
427 #ifdef CONFIG_LOCK_STAT
429 extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
430 extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);
432 #define LOCK_CONTENDED(_lock, try, lock) \
435 lock_contended(&(_lock)->dep_map, _RET_IP_); \
438 lock_acquired(&(_lock)->dep_map, _RET_IP_); \
441 #define LOCK_CONTENDED_RETURN(_lock, try, lock) \
445 lock_contended(&(_lock)->dep_map, _RET_IP_); \
446 ____err = lock(_lock); \
449 lock_acquired(&(_lock)->dep_map, _RET_IP_); \
453 #else /* CONFIG_LOCK_STAT */
455 #define lock_contended(lockdep_map, ip) do {} while (0)
456 #define lock_acquired(lockdep_map, ip) do {} while (0)
458 #define LOCK_CONTENDED(_lock, try, lock) \
461 #define LOCK_CONTENDED_RETURN(_lock, try, lock) \
464 #endif /* CONFIG_LOCK_STAT */
466 #ifdef CONFIG_LOCKDEP
469 * On lockdep we dont want the hand-coded irq-enable of
470 * _raw_*_lock_flags() code, because lockdep assumes
471 * that interrupts are not re-enabled during lock-acquire:
473 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
474 LOCK_CONTENDED((_lock), (try), (lock))
476 #else /* CONFIG_LOCKDEP */
478 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
479 lockfl((_lock), (flags))
481 #endif /* CONFIG_LOCKDEP */
483 #ifdef CONFIG_PROVE_LOCKING
484 extern void print_irqtrace_events(struct task_struct *curr);
486 static inline void print_irqtrace_events(struct task_struct *curr)
491 /* Variable used to make lockdep treat read_lock() as recursive in selftests */
492 #ifdef CONFIG_DEBUG_LOCKING_API_SELFTESTS
493 extern unsigned int force_read_lock_recursive;
494 #else /* CONFIG_DEBUG_LOCKING_API_SELFTESTS */
495 #define force_read_lock_recursive 0
496 #endif /* CONFIG_DEBUG_LOCKING_API_SELFTESTS */
498 #ifdef CONFIG_LOCKDEP
499 extern bool read_lock_is_recursive(void);
500 #else /* CONFIG_LOCKDEP */
501 /* If !LOCKDEP, the value is meaningless */
502 #define read_lock_is_recursive() 0
506 * For trivial one-depth nesting of a lock-class, the following
507 * global define can be used. (Subsystems with multiple levels
508 * of nesting should define their own lock-nesting subclasses.)
510 #define SINGLE_DEPTH_NESTING 1
513 * Map the dependency ops to NOP or to real lockdep ops, depending
514 * on the per lock-class debug mode:
517 #define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i)
518 #define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i)
519 #define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i)
521 #define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
522 #define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
523 #define spin_release(l, i) lock_release(l, i)
525 #define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
526 #define rwlock_acquire_read(l, s, t, i) \
528 if (read_lock_is_recursive()) \
529 lock_acquire_shared_recursive(l, s, t, NULL, i); \
531 lock_acquire_shared(l, s, t, NULL, i); \
534 #define rwlock_release(l, i) lock_release(l, i)
536 #define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
537 #define seqcount_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i)
538 #define seqcount_release(l, i) lock_release(l, i)
540 #define mutex_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
541 #define mutex_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
542 #define mutex_release(l, i) lock_release(l, i)
544 #define rwsem_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
545 #define rwsem_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
546 #define rwsem_acquire_read(l, s, t, i) lock_acquire_shared(l, s, t, NULL, i)
547 #define rwsem_release(l, i) lock_release(l, i)
549 #define lock_map_acquire(l) lock_acquire_exclusive(l, 0, 0, NULL, _THIS_IP_)
550 #define lock_map_acquire_read(l) lock_acquire_shared_recursive(l, 0, 0, NULL, _THIS_IP_)
551 #define lock_map_acquire_tryread(l) lock_acquire_shared_recursive(l, 0, 1, NULL, _THIS_IP_)
552 #define lock_map_release(l) lock_release(l, _THIS_IP_)
554 #ifdef CONFIG_PROVE_LOCKING
555 # define might_lock(lock) \
557 typecheck(struct lockdep_map *, &(lock)->dep_map); \
558 lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_); \
559 lock_release(&(lock)->dep_map, _THIS_IP_); \
561 # define might_lock_read(lock) \
563 typecheck(struct lockdep_map *, &(lock)->dep_map); \
564 lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_); \
565 lock_release(&(lock)->dep_map, _THIS_IP_); \
567 # define might_lock_nested(lock, subclass) \
569 typecheck(struct lockdep_map *, &(lock)->dep_map); \
570 lock_acquire(&(lock)->dep_map, subclass, 0, 1, 1, NULL, \
572 lock_release(&(lock)->dep_map, _THIS_IP_); \
575 DECLARE_PER_CPU(int, hardirqs_enabled);
576 DECLARE_PER_CPU(int, hardirq_context);
577 DECLARE_PER_CPU(unsigned int, lockdep_recursion);
579 #define __lockdep_enabled (debug_locks && !this_cpu_read(lockdep_recursion))
581 #define lockdep_assert_irqs_enabled() \
583 WARN_ON_ONCE(__lockdep_enabled && !this_cpu_read(hardirqs_enabled)); \
586 #define lockdep_assert_irqs_disabled() \
588 WARN_ON_ONCE(__lockdep_enabled && this_cpu_read(hardirqs_enabled)); \
591 #define lockdep_assert_in_irq() \
593 WARN_ON_ONCE(__lockdep_enabled && !this_cpu_read(hardirq_context)); \
596 #define lockdep_assert_preemption_enabled() \
598 WARN_ON_ONCE(IS_ENABLED(CONFIG_PREEMPT_COUNT) && \
599 __lockdep_enabled && \
600 (preempt_count() != 0 || \
601 !this_cpu_read(hardirqs_enabled))); \
604 #define lockdep_assert_preemption_disabled() \
606 WARN_ON_ONCE(IS_ENABLED(CONFIG_PREEMPT_COUNT) && \
607 __lockdep_enabled && \
608 (preempt_count() == 0 && \
609 this_cpu_read(hardirqs_enabled))); \
613 * Acceptable for protecting per-CPU resources accessed from BH.
614 * Much like in_softirq() - semantics are ambiguous, use carefully.
616 #define lockdep_assert_in_softirq() \
618 WARN_ON_ONCE(__lockdep_enabled && \
619 (!in_softirq() || in_irq() || in_nmi())); \
623 # define might_lock(lock) do { } while (0)
624 # define might_lock_read(lock) do { } while (0)
625 # define might_lock_nested(lock, subclass) do { } while (0)
627 # define lockdep_assert_irqs_enabled() do { } while (0)
628 # define lockdep_assert_irqs_disabled() do { } while (0)
629 # define lockdep_assert_in_irq() do { } while (0)
631 # define lockdep_assert_preemption_enabled() do { } while (0)
632 # define lockdep_assert_preemption_disabled() do { } while (0)
633 # define lockdep_assert_in_softirq() do { } while (0)
636 #ifdef CONFIG_PROVE_RAW_LOCK_NESTING
638 # define lockdep_assert_RT_in_threaded_ctx() do { \
639 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
640 lockdep_hardirq_context() && \
641 !(current->hardirq_threaded || current->irq_config), \
642 "Not in threaded context on PREEMPT_RT as expected\n"); \
647 # define lockdep_assert_RT_in_threaded_ctx() do { } while (0)
651 #ifdef CONFIG_LOCKDEP
652 void lockdep_rcu_suspicious(const char *file, const int line, const char *s);
655 lockdep_rcu_suspicious(const char *file, const int line, const char *s)
660 #endif /* __LINUX_LOCKDEP_H */