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
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
;
334 struct lock_class
*lockdep_hlock_class(struct held_lock
*hlock
);
341 * 0: exclusive (write) acquire
342 * 1: read-acquire (no recursion allowed)
343 * 2: read-acquire with same-instance recursion allowed
347 * 0: simple checks (freeing, held-at-exit-time, etc.)
350 extern void lock_acquire(struct lockdep_map
*lock
, unsigned int subclass
,
351 int trylock
, int read
, int check
,
352 struct lockdep_map
*nest_lock
, unsigned long ip
);
354 extern void lock_release(struct lockdep_map
*lock
, int nested
,
358 * Same "read" as for lock_acquire(), except -1 means any.
360 extern int lock_is_held_type(const struct lockdep_map
*lock
, int read
);
362 static inline int lock_is_held(const struct lockdep_map
*lock
)
364 return lock_is_held_type(lock
, -1);
367 #define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map)
368 #define lockdep_is_held_type(lock, r) lock_is_held_type(&(lock)->dep_map, (r))
370 extern void lock_set_class(struct lockdep_map
*lock
, const char *name
,
371 struct lock_class_key
*key
, unsigned int subclass
,
374 static inline void lock_set_subclass(struct lockdep_map
*lock
,
375 unsigned int subclass
, unsigned long ip
)
377 lock_set_class(lock
, lock
->name
, lock
->key
, subclass
, ip
);
380 extern void lock_downgrade(struct lockdep_map
*lock
, unsigned long ip
);
382 struct pin_cookie
{ unsigned int val
; };
384 #define NIL_COOKIE (struct pin_cookie){ .val = 0U, }
386 extern struct pin_cookie
lock_pin_lock(struct lockdep_map
*lock
);
387 extern void lock_repin_lock(struct lockdep_map
*lock
, struct pin_cookie
);
388 extern void lock_unpin_lock(struct lockdep_map
*lock
, struct pin_cookie
);
390 #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
392 #define lockdep_assert_held(l) do { \
393 WARN_ON(debug_locks && !lockdep_is_held(l)); \
396 #define lockdep_assert_held_write(l) do { \
397 WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \
400 #define lockdep_assert_held_read(l) do { \
401 WARN_ON(debug_locks && !lockdep_is_held_type(l, 1)); \
404 #define lockdep_assert_held_once(l) do { \
405 WARN_ON_ONCE(debug_locks && !lockdep_is_held(l)); \
408 #define lockdep_recursing(tsk) ((tsk)->lockdep_recursion)
410 #define lockdep_pin_lock(l) lock_pin_lock(&(l)->dep_map)
411 #define lockdep_repin_lock(l,c) lock_repin_lock(&(l)->dep_map, (c))
412 #define lockdep_unpin_lock(l,c) lock_unpin_lock(&(l)->dep_map, (c))
414 #else /* !CONFIG_LOCKDEP */
416 static inline void lockdep_init_task(struct task_struct
*task
)
420 static inline void lockdep_off(void)
424 static inline void lockdep_on(void)
428 static inline void lockdep_set_selftest_task(struct task_struct
*task
)
432 # define lock_acquire(l, s, t, r, c, n, i) do { } while (0)
433 # define lock_release(l, n, i) do { } while (0)
434 # define lock_downgrade(l, i) do { } while (0)
435 # define lock_set_class(l, n, k, s, i) do { } while (0)
436 # define lock_set_subclass(l, s, i) do { } while (0)
437 # define lockdep_init() do { } while (0)
438 # define lockdep_init_map(lock, name, key, sub) \
439 do { (void)(name); (void)(key); } while (0)
440 # define lockdep_set_class(lock, key) do { (void)(key); } while (0)
441 # define lockdep_set_class_and_name(lock, key, name) \
442 do { (void)(key); (void)(name); } while (0)
443 #define lockdep_set_class_and_subclass(lock, key, sub) \
444 do { (void)(key); } while (0)
445 #define lockdep_set_subclass(lock, sub) do { } while (0)
447 #define lockdep_set_novalidate_class(lock) do { } while (0)
450 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
451 * case since the result is not well defined and the caller should rather
452 * #ifdef the call himself.
455 # define lockdep_reset() do { debug_locks = 1; } while (0)
456 # define lockdep_free_key_range(start, size) do { } while (0)
457 # define lockdep_sys_exit() do { } while (0)
459 * The class key takes no space if lockdep is disabled:
461 struct lock_class_key
{ };
463 static inline void lockdep_register_key(struct lock_class_key
*key
)
467 static inline void lockdep_unregister_key(struct lock_class_key
*key
)
472 * The lockdep_map takes no space if lockdep is disabled:
474 struct lockdep_map
{ };
476 #define lockdep_depth(tsk) (0)
478 #define lockdep_is_held(lock) (1)
479 #define lockdep_is_held_type(l, r) (1)
481 #define lockdep_assert_held(l) do { (void)(l); } while (0)
482 #define lockdep_assert_held_write(l) do { (void)(l); } while (0)
483 #define lockdep_assert_held_read(l) do { (void)(l); } while (0)
484 #define lockdep_assert_held_once(l) do { (void)(l); } while (0)
486 #define lockdep_recursing(tsk) (0)
488 struct pin_cookie
{ };
490 #define NIL_COOKIE (struct pin_cookie){ }
492 #define lockdep_pin_lock(l) ({ struct pin_cookie cookie = { }; cookie; })
493 #define lockdep_repin_lock(l, c) do { (void)(l); (void)(c); } while (0)
494 #define lockdep_unpin_lock(l, c) do { (void)(l); (void)(c); } while (0)
496 #endif /* !LOCKDEP */
498 enum xhlock_context_t
{
504 #define lockdep_init_map_crosslock(m, n, k, s) do {} while (0)
506 * To initialize a lockdep_map statically use this macro.
507 * Note that _name must not be NULL.
509 #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
510 { .name = (_name), .key = (void *)(_key), }
512 static inline void lockdep_invariant_state(bool force
) {}
513 static inline void lockdep_free_task(struct task_struct
*task
) {}
515 #ifdef CONFIG_LOCK_STAT
517 extern void lock_contended(struct lockdep_map
*lock
, unsigned long ip
);
518 extern void lock_acquired(struct lockdep_map
*lock
, unsigned long ip
);
520 #define LOCK_CONTENDED(_lock, try, lock) \
523 lock_contended(&(_lock)->dep_map, _RET_IP_); \
526 lock_acquired(&(_lock)->dep_map, _RET_IP_); \
529 #define LOCK_CONTENDED_RETURN(_lock, try, lock) \
533 lock_contended(&(_lock)->dep_map, _RET_IP_); \
534 ____err = lock(_lock); \
537 lock_acquired(&(_lock)->dep_map, _RET_IP_); \
541 #else /* CONFIG_LOCK_STAT */
543 #define lock_contended(lockdep_map, ip) do {} while (0)
544 #define lock_acquired(lockdep_map, ip) do {} while (0)
546 #define LOCK_CONTENDED(_lock, try, lock) \
549 #define LOCK_CONTENDED_RETURN(_lock, try, lock) \
552 #endif /* CONFIG_LOCK_STAT */
554 #ifdef CONFIG_LOCKDEP
557 * On lockdep we dont want the hand-coded irq-enable of
558 * _raw_*_lock_flags() code, because lockdep assumes
559 * that interrupts are not re-enabled during lock-acquire:
561 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
562 LOCK_CONTENDED((_lock), (try), (lock))
564 #else /* CONFIG_LOCKDEP */
566 #define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
567 lockfl((_lock), (flags))
569 #endif /* CONFIG_LOCKDEP */
571 #ifdef CONFIG_PROVE_LOCKING
572 extern void print_irqtrace_events(struct task_struct
*curr
);
574 static inline void print_irqtrace_events(struct task_struct
*curr
)
580 * For trivial one-depth nesting of a lock-class, the following
581 * global define can be used. (Subsystems with multiple levels
582 * of nesting should define their own lock-nesting subclasses.)
584 #define SINGLE_DEPTH_NESTING 1
587 * Map the dependency ops to NOP or to real lockdep ops, depending
588 * on the per lock-class debug mode:
591 #define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i)
592 #define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i)
593 #define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i)
595 #define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
596 #define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
597 #define spin_release(l, n, i) lock_release(l, n, i)
599 #define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
600 #define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i)
601 #define rwlock_release(l, n, i) lock_release(l, n, i)
603 #define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
604 #define seqcount_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i)
605 #define seqcount_release(l, n, i) lock_release(l, n, i)
607 #define mutex_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
608 #define mutex_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
609 #define mutex_release(l, n, i) lock_release(l, n, i)
611 #define rwsem_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
612 #define rwsem_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
613 #define rwsem_acquire_read(l, s, t, i) lock_acquire_shared(l, s, t, NULL, i)
614 #define rwsem_release(l, n, i) lock_release(l, n, i)
616 #define lock_map_acquire(l) lock_acquire_exclusive(l, 0, 0, NULL, _THIS_IP_)
617 #define lock_map_acquire_read(l) lock_acquire_shared_recursive(l, 0, 0, NULL, _THIS_IP_)
618 #define lock_map_acquire_tryread(l) lock_acquire_shared_recursive(l, 0, 1, NULL, _THIS_IP_)
619 #define lock_map_release(l) lock_release(l, 1, _THIS_IP_)
621 #ifdef CONFIG_PROVE_LOCKING
622 # define might_lock(lock) \
624 typecheck(struct lockdep_map *, &(lock)->dep_map); \
625 lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_); \
626 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
628 # define might_lock_read(lock) \
630 typecheck(struct lockdep_map *, &(lock)->dep_map); \
631 lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_); \
632 lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
635 #define lockdep_assert_irqs_enabled() do { \
636 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
637 !current->hardirqs_enabled, \
638 "IRQs not enabled as expected\n"); \
641 #define lockdep_assert_irqs_disabled() do { \
642 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
643 current->hardirqs_enabled, \
644 "IRQs not disabled as expected\n"); \
647 #define lockdep_assert_in_irq() do { \
648 WARN_ONCE(debug_locks && !current->lockdep_recursion && \
649 !current->hardirq_context, \
650 "Not in hardirq as expected\n"); \
654 # define might_lock(lock) do { } while (0)
655 # define might_lock_read(lock) do { } while (0)
656 # define lockdep_assert_irqs_enabled() do { } while (0)
657 # define lockdep_assert_irqs_disabled() do { } while (0)
658 # define lockdep_assert_in_irq() do { } while (0)
661 #ifdef CONFIG_LOCKDEP
662 void lockdep_rcu_suspicious(const char *file
, const int line
, const char *s
);
665 lockdep_rcu_suspicious(const char *file
, const int line
, const char *s
)
670 #endif /* __LINUX_LOCKDEP_H */