diff options
Diffstat (limited to 'kernel/locking')
| -rw-r--r-- | kernel/locking/lockdep.c | 741 | ||||
| -rw-r--r-- | kernel/locking/locktorture.c | 108 | ||||
| -rw-r--r-- | kernel/locking/qspinlock.c | 12 | ||||
| -rw-r--r-- | kernel/locking/rtmutex.c | 26 | ||||
| -rw-r--r-- | kernel/locking/rtmutex_common.h | 1 | ||||
| -rw-r--r-- | kernel/locking/spinlock.c | 13 |
6 files changed, 163 insertions, 738 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 670d8d7..89b5f83 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -49,6 +49,7 @@ #include <linux/gfp.h> #include <linux/random.h> #include <linux/jhash.h> +#include <linux/nmi.h> #include <asm/sections.h> @@ -57,10 +58,6 @@ #define CREATE_TRACE_POINTS #include <trace/events/lock.h> -#ifdef CONFIG_LOCKDEP_CROSSRELEASE -#include <linux/slab.h> -#endif - #ifdef CONFIG_PROVE_LOCKING int prove_locking = 1; module_param(prove_locking, int, 0644); @@ -75,19 +72,6 @@ module_param(lock_stat, int, 0644); #define lock_stat 0 #endif -#ifdef CONFIG_BOOTPARAM_LOCKDEP_CROSSRELEASE_FULLSTACK -static int crossrelease_fullstack = 1; -#else -static int crossrelease_fullstack; -#endif -static int __init allow_crossrelease_fullstack(char *str) -{ - crossrelease_fullstack = 1; - return 0; -} - -early_param("crossrelease_fullstack", allow_crossrelease_fullstack); - /* * lockdep_lock: protects the lockdep graph, the hashes and the * class/list/hash allocators. @@ -664,18 +648,12 @@ static int count_matching_names(struct lock_class *new_class) return count + 1; } -/* - * Register a lock's class in the hash-table, if the class is not present - * yet. Otherwise we look it up. We cache the result in the lock object - * itself, so actual lookup of the hash should be once per lock object. - */ static inline struct lock_class * -look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) +look_up_lock_class(const struct lockdep_map *lock, unsigned int subclass) { struct lockdep_subclass_key *key; struct hlist_head *hash_head; struct lock_class *class; - bool is_static = false; if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { debug_locks_off(); @@ -688,24 +666,11 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) } /* - * Static locks do not have their class-keys yet - for them the key - * is the lock object itself. If the lock is in the per cpu area, - * the canonical address of the lock (per cpu offset removed) is - * used. + * If it is not initialised then it has never been locked, + * so it won't be present in the hash table. */ - if (unlikely(!lock->key)) { - unsigned long can_addr, addr = (unsigned long)lock; - - if (__is_kernel_percpu_address(addr, &can_addr)) - lock->key = (void *)can_addr; - else if (__is_module_percpu_address(addr, &can_addr)) - lock->key = (void *)can_addr; - else if (static_obj(lock)) - lock->key = (void *)lock; - else - return ERR_PTR(-EINVAL); - is_static = true; - } + if (unlikely(!lock->key)) + return NULL; /* * NOTE: the class-key must be unique. For dynamic locks, a static @@ -737,20 +702,36 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) } } - return is_static || static_obj(lock->key) ? NULL : ERR_PTR(-EINVAL); + return NULL; } -#ifdef CONFIG_LOCKDEP_CROSSRELEASE -static void cross_init(struct lockdep_map *lock, int cross); -static int cross_lock(struct lockdep_map *lock); -static int lock_acquire_crosslock(struct held_lock *hlock); -static int lock_release_crosslock(struct lockdep_map *lock); -#else -static inline void cross_init(struct lockdep_map *lock, int cross) {} -static inline int cross_lock(struct lockdep_map *lock) { return 0; } -static inline int lock_acquire_crosslock(struct held_lock *hlock) { return 2; } -static inline int lock_release_crosslock(struct lockdep_map *lock) { return 2; } -#endif +/* + * Static locks do not have their class-keys yet - for them the key is + * the lock object itself. If the lock is in the per cpu area, the + * canonical address of the lock (per cpu offset removed) is used. + */ +static bool assign_lock_key(struct lockdep_map *lock) +{ + unsigned long can_addr, addr = (unsigned long)lock; + + if (__is_kernel_percpu_address(addr, &can_addr)) + lock->key = (void *)can_addr; + else if (__is_module_percpu_address(addr, &can_addr)) + lock->key = (void *)can_addr; + else if (static_obj(lock)) + lock->key = (void *)lock; + else { + /* Debug-check: all keys must be persistent! */ + debug_locks_off(); + pr_err("INFO: trying to register non-static key.\n"); + pr_err("the code is fine but needs lockdep annotation.\n"); + pr_err("turning off the locking correctness validator.\n"); + dump_stack(); + return false; + } + + return true; +} /* * Register a lock's class in the hash-table, if the class is not present @@ -767,18 +748,13 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) DEBUG_LOCKS_WARN_ON(!irqs_disabled()); class = look_up_lock_class(lock, subclass); - if (likely(!IS_ERR_OR_NULL(class))) + if (likely(class)) goto out_set_class_cache; - /* - * Debug-check: all keys must be persistent! - */ - if (IS_ERR(class)) { - debug_locks_off(); - printk("INFO: trying to register non-static key.\n"); - printk("the code is fine but needs lockdep annotation.\n"); - printk("turning off the locking correctness validator.\n"); - dump_stack(); + if (!lock->key) { + if (!assign_lock_key(lock)) + return NULL; + } else if (!static_obj(lock->key)) { return NULL; } @@ -1151,41 +1127,22 @@ print_circular_lock_scenario(struct held_lock *src, printk(KERN_CONT "\n\n"); } - if (cross_lock(tgt->instance)) { - printk(" Possible unsafe locking scenario by crosslock:\n\n"); - printk(" CPU0 CPU1\n"); - printk(" ---- ----\n"); - printk(" lock("); - __print_lock_name(parent); - printk(KERN_CONT ");\n"); - printk(" lock("); - __print_lock_name(target); - printk(KERN_CONT ");\n"); - printk(" lock("); - __print_lock_name(source); - printk(KERN_CONT ");\n"); - printk(" unlock("); - __print_lock_name(target); - printk(KERN_CONT ");\n"); - printk("\n *** DEADLOCK ***\n\n"); - } else { - printk(" Possible unsafe locking scenario:\n\n"); - printk(" CPU0 CPU1\n"); - printk(" ---- ----\n"); - printk(" lock("); - __print_lock_name(target); - printk(KERN_CONT ");\n"); - printk(" lock("); - __print_lock_name(parent); - printk(KERN_CONT ");\n"); - printk(" lock("); - __print_lock_name(target); - printk(KERN_CONT ");\n"); - printk(" lock("); - __print_lock_name(source); - printk(KERN_CONT ");\n"); - printk("\n *** DEADLOCK ***\n\n"); - } + printk(" Possible unsafe locking scenario:\n\n"); + printk(" CPU0 CPU1\n"); + printk(" ---- ----\n"); + printk(" lock("); + __print_lock_name(target); + printk(KERN_CONT ");\n"); + printk(" lock("); + __print_lock_name(parent); + printk(KERN_CONT ");\n"); + printk(" lock("); + __print_lock_name(target); + printk(KERN_CONT ");\n"); + printk(" lock("); + __print_lock_name(source); + printk(KERN_CONT ");\n"); + printk("\n *** DEADLOCK ***\n\n"); } /* @@ -1211,10 +1168,7 @@ print_circular_bug_header(struct lock_list *entry, unsigned int depth, curr->comm, task_pid_nr(curr)); print_lock(check_src); - if (cross_lock(check_tgt->instance)) - pr_warn("\nbut now in release context of a crosslock acquired at the following:\n"); - else - pr_warn("\nbut task is already holding lock:\n"); + pr_warn("\nbut task is already holding lock:\n"); print_lock(check_tgt); pr_warn("\nwhich lock already depends on the new lock.\n\n"); @@ -1244,9 +1198,7 @@ static noinline int print_circular_bug(struct lock_list *this, if (!debug_locks_off_graph_unlock() || debug_locks_silent) return 0; - if (cross_lock(check_tgt->instance)) - this->trace = *trace; - else if (!save_trace(&this->trace)) + if (!save_trace(&this->trace)) return 0; depth = get_lock_depth(target); @@ -1850,9 +1802,6 @@ check_deadlock(struct task_struct *curr, struct held_lock *next, if (nest) return 2; - if (cross_lock(prev->instance)) - continue; - return print_deadlock_bug(curr, prev, next); } return 1; @@ -2018,31 +1967,26 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) for (;;) { int distance = curr->lockdep_depth - depth + 1; hlock = curr->held_locks + depth - 1; + /* - * Only non-crosslock entries get new dependencies added. - * Crosslock entries will be added by commit later: + * Only non-recursive-read entries get new dependencies + * added: */ - if (!cross_lock(hlock->instance)) { + if (hlock->read != 2 && hlock->check) { + int ret = check_prev_add(curr, hlock, next, distance, &trace, save_trace); + if (!ret) + return 0; + /* - * Only non-recursive-read entries get new dependencies - * added: + * Stop after the first non-trylock entry, + * as non-trylock entries have added their + * own direct dependencies already, so this + * lock is connected to them indirectly: */ - if (hlock->read != 2 && hlock->check) { - int ret = check_prev_add(curr, hlock, next, - distance, &trace, save_trace); - if (!ret) - return 0; - - /* - * Stop after the first non-trylock entry, - * as non-trylock entries have added their - * own direct dependencies already, so this - * lock is connected to them indirectly: - */ - if (!hlock->trylock) - break; - } + if (!hlock->trylock) + break; } + depth--; /* * End of lock-stack? @@ -3292,21 +3236,10 @@ static void __lockdep_init_map(struct lockdep_map *lock, const char *name, void lockdep_init_map(struct lockdep_map *lock, const char *name, struct lock_class_key *key, int subclass) { - cross_init(lock, 0); __lockdep_init_map(lock, name, key, subclass); } EXPORT_SYMBOL_GPL(lockdep_init_map); -#ifdef CONFIG_LOCKDEP_CROSSRELEASE -void lockdep_init_map_crosslock(struct lockdep_map *lock, const char *name, - struct lock_class_key *key, int subclass) -{ - cross_init(lock, 1); - __lockdep_init_map(lock, name, key, subclass); -} -EXPORT_SYMBOL_GPL(lockdep_init_map_crosslock); -#endif - struct lock_class_key __lockdep_no_validate__; EXPORT_SYMBOL_GPL(__lockdep_no_validate__); @@ -3344,7 +3277,7 @@ print_lock_nested_lock_not_held(struct task_struct *curr, return 0; } -static int __lock_is_held(struct lockdep_map *lock, int read); +static int __lock_is_held(const struct lockdep_map *lock, int read); /* * This gets called for every mutex_lock*()/spin_lock*() operation. @@ -3362,7 +3295,6 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, int chain_head = 0; int class_idx; u64 chain_key; - int ret; if (unlikely(!debug_locks)) return 0; @@ -3411,8 +3343,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, class_idx = class - lock_classes + 1; - /* TODO: nest_lock is not implemented for crosslock yet. */ - if (depth && !cross_lock(lock)) { + if (depth) { hlock = curr->held_locks + depth - 1; if (hlock->class_idx == class_idx && nest_lock) { if (hlock->references) { @@ -3500,14 +3431,6 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) return 0; - ret = lock_acquire_crosslock(hlock); - /* - * 2 means normal acquire operations are needed. Otherwise, it's - * ok just to return with '0:fail, 1:success'. - */ - if (ret != 2) - return ret; - curr->curr_chain_key = chain_key; curr->lockdep_depth++; check_chain_key(curr); @@ -3563,13 +3486,14 @@ print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, return 0; } -static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) +static int match_held_lock(const struct held_lock *hlock, + const struct lockdep_map *lock) { if (hlock->instance == lock) return 1; if (hlock->references) { - struct lock_class *class = lock->class_cache[0]; + const struct lock_class *class = lock->class_cache[0]; if (!class) class = look_up_lock_class(lock, 0); @@ -3580,7 +3504,7 @@ static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) * Clearly if the lock hasn't been acquired _ever_, we're not * holding it either, so report failure. */ - if (IS_ERR_OR_NULL(class)) + if (!class) return 0; /* @@ -3745,19 +3669,11 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) struct task_struct *curr = current; struct held_lock *hlock; unsigned int depth; - int ret, i; + int i; if (unlikely(!debug_locks)) return 0; - ret = lock_release_crosslock(lock); - /* - * 2 means normal release operations are needed. Otherwise, it's - * ok just to return with '0:fail, 1:success'. - */ - if (ret != 2) - return ret; - depth = curr->lockdep_depth; /* * So we're all set to release this lock.. wait what lock? We don't @@ -3813,7 +3729,7 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) return 1; } -static int __lock_is_held(struct lockdep_map *lock, int read) +static int __lock_is_held(const struct lockdep_map *lock, int read) { struct task_struct *curr = current; int i; @@ -4027,7 +3943,7 @@ void lock_release(struct lockdep_map *lock, int nested, } EXPORT_SYMBOL_GPL(lock_release); -int lock_is_held_type(struct lockdep_map *lock, int read) +int lock_is_held_type(const struct lockdep_map *lock, int read) { unsigned long flags; int ret = 0; @@ -4384,7 +4300,7 @@ void lockdep_reset_lock(struct lockdep_map *lock) * If the class exists we look it up and zap it: */ class = look_up_lock_class(lock, j); - if (!IS_ERR_OR_NULL(class)) + if (class) zap_class(class); } /* @@ -4580,6 +4496,7 @@ retry: if (!unlock) if (read_trylock(&tasklist_lock)) unlock = 1; + touch_nmi_watchdog(); } while_each_thread(g, p); pr_warn("\n"); @@ -4675,495 +4592,3 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s) dump_stack(); } EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); - -#ifdef CONFIG_LOCKDEP_CROSSRELEASE - -/* - * Crossrelease works by recording a lock history for each thread and - * connecting those historic locks that were taken after the - * wait_for_completion() in the complete() context. - * - * Task-A Task-B - * - * mutex_lock(&A); - * mutex_unlock(&A); - * - * wait_for_completion(&C); - * lock_acquire_crosslock(); - * atomic_inc_return(&cross_gen_id); - * | - * | mutex_lock(&B); - * | mutex_unlock(&B); - * | - * | complete(&C); - * `-- lock_commit_crosslock(); - * - * Which will then add a dependency between B and C. - */ - -#define xhlock(i) (current->xhlocks[(i) % MAX_XHLOCKS_NR]) - -/* - * Whenever a crosslock is held, cross_gen_id will be increased. - */ -static atomic_t cross_gen_id; /* Can be wrapped */ - -/* - * Make an entry of the ring buffer invalid. - */ -static inline void invalidate_xhlock(struct hist_lock *xhlock) -{ - /* - * Normally, xhlock->hlock.instance must be !NULL. - */ - xhlock->hlock.instance = NULL; -} - -/* - * Lock history stacks; we have 2 nested lock history stacks: - * - * HARD(IRQ) - * SOFT(IRQ) - * - * The thing is that once we complete a HARD/SOFT IRQ the future task locks - * should not depend on any of the locks observed while running the IRQ. So - * what we do is rewind the history buffer and erase all our knowledge of that - * temporal event. - */ - -void crossrelease_hist_start(enum xhlock_context_t c) -{ - struct task_struct *cur = current; - - if (!cur->xhlocks) - return; - - cur->xhlock_idx_hist[c] = cur->xhlock_idx; - cur->hist_id_save[c] = cur->hist_id; -} - -void crossrelease_hist_end(enum xhlock_context_t c) -{ - struct task_struct *cur = current; - - if (cur->xhlocks) { - unsigned int idx = cur->xhlock_idx_hist[c]; - struct hist_lock *h = &xhlock(idx); - - cur->xhlock_idx = idx; - - /* Check if the ring was overwritten. */ - if (h->hist_id != cur->hist_id_save[c]) - invalidate_xhlock(h); - } -} - -/* - * lockdep_invariant_state() is used to annotate independence inside a task, to - * make one task look like multiple independent 'tasks'. - * - * Take for instance workqueues; each work is independent of the last. The - * completion of a future work does not depend on the completion of a past work - * (in general). Therefore we must not carry that (lock) dependency across - * works. - * - * This is true for many things; pretty much all kthreads fall into this - * pattern, where they have an invariant state and future completions do not - * depend on past completions. Its just that since they all have the 'same' - * form -- the kthread does the same over and over -- it doesn't typically - * matter. - * - * The same is true for system-calls, once a system call is completed (we've - * returned to userspace) the next system call does not depend on the lock - * history of the previous system call. - * - * They key property for independence, this invariant state, is that it must be - * a point where we hold no locks and have no history. Because if we were to - * hold locks, the restore at _end() would not necessarily recover it's history - * entry. Similarly, independence per-definition means it does not depend on - * prior state. - */ -void lockdep_invariant_state(bool force) -{ - /* - * We call this at an invariant point, no current state, no history. - * Verify the former, enforce the latter. - */ - WARN_ON_ONCE(!force && current->lockdep_depth); - if (current->xhlocks) - invalidate_xhlock(&xhlock(current->xhlock_idx)); -} - -static int cross_lock(struct lockdep_map *lock) -{ - return lock ? lock->cross : 0; -} - -/* - * This is needed to decide the relationship between wrapable variables. - */ -static inline int before(unsigned int a, unsigned int b) -{ - return (int)(a - b) < 0; -} - -static inline struct lock_class *xhlock_class(struct hist_lock *xhlock) -{ - return hlock_class(&xhlock->hlock); -} - -static inline struct lock_class *xlock_class(struct cross_lock *xlock) -{ - return hlock_class(&xlock->hlock); -} - -/* - * Should we check a dependency with previous one? - */ -static inline int depend_before(struct held_lock *hlock) -{ - return hlock->read != 2 && hlock->check && !hlock->trylock; -} - -/* - * Should we check a dependency with next one? - */ -static inline int depend_after(struct held_lock *hlock) -{ - return hlock->read != 2 && hlock->check; -} - -/* - * Check if the xhlock is valid, which would be false if, - * - * 1. Has not used after initializaion yet. - * 2. Got invalidated. - * - * Remind hist_lock is implemented as a ring buffer. - */ -static inline int xhlock_valid(struct hist_lock *xhlock) -{ - /* - * xhlock->hlock.instance must be !NULL. - */ - return !!xhlock->hlock.instance; -} - -/* - * Record a hist_lock entry. - * - * Irq disable is only required. - */ -static void add_xhlock(struct held_lock *hlock) -{ - unsigned int idx = ++current->xhlock_idx; - struct hist_lock *xhlock = &xhlock(idx); - -#ifdef CONFIG_DEBUG_LOCKDEP - /* - * This can be done locklessly because they are all task-local - * state, we must however ensure IRQs are disabled. - */ - WARN_ON_ONCE(!irqs_disabled()); -#endif - - /* Initialize hist_lock's members */ - xhlock->hlock = *hlock; - xhlock->hist_id = ++current->hist_id; - - xhlock->trace.nr_entries = 0; - xhlock->trace.max_entries = MAX_XHLOCK_TRACE_ENTRIES; - xhlock->trace.entries = xhlock->trace_entries; - - if (crossrelease_fullstack) { - xhlock->trace.skip = 3; - save_stack_trace(&xhlock->trace); - } else { - xhlock->trace.nr_entries = 1; - xhlock->trace.entries[0] = hlock->acquire_ip; - } -} - -static inline int same_context_xhlock(struct hist_lock *xhlock) -{ - return xhlock->hlock.irq_context == task_irq_context(current); -} - -/* - * This should be lockless as far as possible because this would be - * called very frequently. - */ -static void check_add_xhlock(struct held_lock *hlock) -{ - /* - * Record a hist_lock, only in case that acquisitions ahead - * could depend on the held_lock. For example, if the held_lock - * is trylock then acquisitions ahead never depends on that. - * In that case, we don't need to record it. Just return. - */ - if (!current->xhlocks || !depend_before(hlock)) - return; - - add_xhlock(hlock); -} - -/* - * For crosslock. - */ -static int add_xlock(struct held_lock *hlock) -{ - struct cross_lock *xlock; - unsigned int gen_id; - - if (!graph_lock()) - return 0; - - xlock = &((struct lockdep_map_cross *)hlock->instance)->xlock; - - /* - * When acquisitions for a crosslock are overlapped, we use - * nr_acquire to perform commit for them, based on cross_gen_id - * of the first acquisition, which allows to add additional - * dependencies. - * - * Moreover, when no acquisition of a crosslock is in progress, - * we should not perform commit because the lock might not exist - * any more, which might cause incorrect memory access. So we - * have to track the number of acquisitions of a crosslock. - * - * depend_after() is necessary to initialize only the first - * valid xlock so that the xlock can be used on its commit. - */ - if (xlock->nr_acquire++ && depend_after(&xlock->hlock)) - goto unlock; - - gen_id = (unsigned int)atomic_inc_return(&cross_gen_id); - xlock->hlock = *hlock; - xlock->hlock.gen_id = gen_id; -unlock: - graph_unlock(); - return 1; -} - -/* - * Called for both normal and crosslock acquires. Normal locks will be - * pushed on the hist_lock queue. Cross locks will record state and - * stop regular lock_acquire() to avoid being placed on the held_lock - * stack. - * - * Return: 0 - failure; - * 1 - crosslock, done; - * 2 - normal lock, continue to held_lock[] ops. - */ -static int lock_acquire_crosslock(struct held_lock *hlock) -{ - /* - * CONTEXT 1 CONTEXT 2 - * --------- --------- - * lock A (cross) - * X = atomic_inc_return(&cross_gen_id) - * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - * Y = atomic_read_acquire(&cross_gen_id) - * lock B - * - * atomic_read_acquire() is for ordering between A and B, - * IOW, A happens before B, when CONTEXT 2 see Y >= X. - * - * Pairs with atomic_inc_return() in add_xlock(). - */ - hlock->gen_id = (unsigned int)atomic_read_acquire(&cross_gen_id); - - if (cross_lock(hlock->instance)) - return add_xlock(hlock); - - check_add_xhlock(hlock); - return 2; -} - -static int copy_trace(struct stack_trace *trace) -{ - unsigned long *buf = stack_trace + nr_stack_trace_entries; - unsigned int max_nr = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; - unsigned int nr = min(max_nr, trace->nr_entries); - - trace->nr_entries = nr; - memcpy(buf, trace->entries, nr * sizeof(trace->entries[0])); - trace->entries = buf; - nr_stack_trace_entries += nr; - - if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { - if (!debug_locks_off_graph_unlock()) - return 0; - - print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!"); - dump_stack(); - - return 0; - } - - return 1; -} - -static int commit_xhlock(struct cross_lock *xlock, struct hist_lock *xhlock) -{ - unsigned int xid, pid; - u64 chain_key; - - xid = xlock_class(xlock) - lock_classes; - chain_key = iterate_chain_key((u64)0, xid); - pid = xhlock_class(xhlock) - lock_classes; - chain_key = iterate_chain_key(chain_key, pid); - - if (lookup_chain_cache(chain_key)) - return 1; - - if (!add_chain_cache_classes(xid, pid, xhlock->hlock.irq_context, - chain_key)) - return 0; - - if (!check_prev_add(current, &xlock->hlock, &xhlock->hlock, 1, - &xhlock->trace, copy_trace)) - return 0; - - return 1; -} - -static void commit_xhlocks(struct cross_lock *xlock) -{ - unsigned int cur = current->xhlock_idx; - unsigned int prev_hist_id = xhlock(cur).hist_id; - unsigned int i; - - if (!graph_lock()) - return; - - if (xlock->nr_acquire) { - for (i = 0; i < MAX_XHLOCKS_NR; i++) { - struct hist_lock *xhlock = &xhlock(cur - i); - - if (!xhlock_valid(xhlock)) - break; - - if (before(xhlock->hlock.gen_id, xlock->hlock.gen_id)) - break; - - if (!same_context_xhlock(xhlock)) - break; - - /* - * Filter out the cases where the ring buffer was - * overwritten and the current entry has a bigger - * hist_id than the previous one, which is impossible - * otherwise: - */ - if (unlikely(before(prev_hist_id, xhlock->hist_id))) - break; - - prev_hist_id = xhlock->hist_id; - - /* - * commit_xhlock() returns 0 with graph_lock already - * released if fail. - */ - if (!commit_xhlock(xlock, xhlock)) - return; - } - } - - graph_unlock(); -} - -void lock_commit_crosslock(struct lockdep_map *lock) -{ - struct cross_lock *xlock; - unsigned long flags; - - if (unlikely(!debug_locks || current->lockdep_recursion)) - return; - - if (!current->xhlocks) - return; - - /* - * Do commit hist_locks with the cross_lock, only in case that - * the cross_lock could depend on acquisitions after that. - * - * For example, if the cross_lock does not have the 'check' flag - * then we don't need to check dependencies and commit for that. - * Just skip it. In that case, of course, the cross_lock does - * not depend on acquisitions ahead, either. - * - * WARNING: Don't do that in add_xlock() in advance. When an - * acquisition context is different from the commit context, - * invalid(skipped) cross_lock might be accessed. - */ - if (!depend_after(&((struct lockdep_map_cross *)lock)->xlock.hlock)) - return; - - raw_local_irq_save(flags); - check_flags(flags); - current->lockdep_recursion = 1; - xlock = &((struct lockdep_map_cross *)lock)->xlock; - commit_xhlocks(xlock); - current->lockdep_recursion = 0; - raw_local_irq_restore(flags); -} -EXPORT_SYMBOL_GPL(lock_commit_crosslock); - -/* - * Return: 0 - failure; - * 1 - crosslock, done; - * 2 - normal lock, continue to held_lock[] ops. - */ -static int lock_release_crosslock(struct lockdep_map *lock) -{ - if (cross_lock(lock)) { - if (!graph_lock()) - return 0; - ((struct lockdep_map_cross *)lock)->xlock.nr_acquire--; - graph_unlock(); - return 1; - } - return 2; -} - -static void cross_init(struct lockdep_map *lock, int cross) -{ - if (cross) - ((struct lockdep_map_cross *)lock)->xlock.nr_acquire = 0; - - lock->cross = cross; - - /* - * Crossrelease assumes that the ring buffer size of xhlocks - * is aligned with power of 2. So force it on build. - */ - BUILD_BUG_ON(MAX_XHLOCKS_NR & (MAX_XHLOCKS_NR - 1)); -} - -void lockdep_init_task(struct task_struct *task) -{ - int i; - - task->xhlock_idx = UINT_MAX; - task->hist_id = 0; - - for (i = 0; i < XHLOCK_CTX_NR; i++) { - task->xhlock_idx_hist[i] = UINT_MAX; - task->hist_id_save[i] = 0; - } - - task->xhlocks = kzalloc(sizeof(struct hist_lock) * MAX_XHLOCKS_NR, - GFP_KERNEL); -} - -void lockdep_free_task(struct task_struct *task) -{ - if (task->xhlocks) { - void *tmp = task->xhlocks; - /* Diable crossrelease for current */ - task->xhlocks = NULL; - kfree(tmp); - } -} -#endif diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index f24582d..6850ffd 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -77,10 +77,6 @@ struct lock_stress_stats { long n_lock_acquired; }; -int torture_runnable = IS_ENABLED(MODULE); -module_param(torture_runnable, int, 0444); -MODULE_PARM_DESC(torture_runnable, "Start locktorture at module init"); - /* Forward reference. */ static void lock_torture_cleanup(void); @@ -130,10 +126,8 @@ static void torture_lock_busted_write_delay(struct torture_random_state *trsp) if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 2000 * longdelay_ms))) mdelay(longdelay_ms); -#ifdef CONFIG_PREEMPT if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) - preempt_schedule(); /* Allow test to be preempted. */ -#endif + torture_preempt_schedule(); /* Allow test to be preempted. */ } static void torture_lock_busted_write_unlock(void) @@ -179,10 +173,8 @@ static void torture_spin_lock_write_delay(struct torture_random_state *trsp) if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 2 * shortdelay_us))) udelay(shortdelay_us); -#ifdef CONFIG_PREEMPT if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) - preempt_schedule(); /* Allow test to be preempted. */ -#endif + torture_preempt_schedule(); /* Allow test to be preempted. */ } static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock) @@ -352,10 +344,8 @@ static void torture_mutex_delay(struct torture_random_state *trsp) mdelay(longdelay_ms * 5); else mdelay(longdelay_ms / 5); -#ifdef CONFIG_PREEMPT if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) - preempt_schedule(); /* Allow test to be preempted. */ -#endif + torture_preempt_schedule(); /* Allow test to be preempted. */ } static void torture_mutex_unlock(void) __releases(torture_mutex) @@ -507,10 +497,8 @@ static void torture_rtmutex_delay(struct torture_random_state *trsp) if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 2 * shortdelay_us))) udelay(shortdelay_us); -#ifdef CONFIG_PREEMPT if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) - preempt_schedule(); /* Allow test to be preempted. */ -#endif + torture_preempt_schedule(); /* Allow test to be preempted. */ } static void torture_rtmutex_unlock(void) __releases(torture_rtmutex) @@ -547,10 +535,8 @@ static void torture_rwsem_write_delay(struct torture_random_state *trsp) mdelay(longdelay_ms * 10); else mdelay(longdelay_ms / 10); -#ifdef CONFIG_PREEMPT if (!(torture_random(trsp) % (cxt.nrealwriters_stress * 20000))) - preempt_schedule(); /* Allow test to be preempted. */ -#endif + torture_preempt_schedule(); /* Allow test to be preempted. */ } static void torture_rwsem_up_write(void) __releases(torture_rwsem) @@ -570,14 +556,12 @@ static void torture_rwsem_read_delay(struct torture_random_state *trsp) /* We want a long delay occasionally to force massive contention. */ if (!(torture_random(trsp) % - (cxt.nrealwriters_stress * 2000 * longdelay_ms))) + (cxt.nrealreaders_stress * 2000 * longdelay_ms))) mdelay(longdelay_ms * 2); else mdelay(longdelay_ms / 2); -#ifdef CONFIG_PREEMPT if (!(torture_random(trsp) % (cxt.nrealreaders_stress * 20000))) - preempt_schedule(); /* Allow test to be preempted. */ -#endif + torture_preempt_schedule(); /* Allow test to be preempted. */ } static void torture_rwsem_up_read(void) __releases(torture_rwsem) @@ -715,8 +699,7 @@ static void __torture_print_stats(char *page, { bool fail = 0; int i, n_stress; - long max = 0; - long min = statp[0].n_lock_acquired; + long max = 0, min = statp ? statp[0].n_lock_acquired : 0; long long sum = 0; n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress; @@ -823,7 +806,7 @@ static void lock_torture_cleanup(void) * such, only perform the underlying torture-specific cleanups, * and avoid anything related to locktorture. */ - if (!cxt.lwsa) + if (!cxt.lwsa && !cxt.lrsa) goto end; if (writer_tasks) { @@ -879,7 +862,7 @@ static int __init lock_torture_init(void) &percpu_rwsem_lock_ops, }; - if (!torture_init_begin(torture_type, verbose, &torture_runnable)) + if (!torture_init_begin(torture_type, verbose)) return -EBUSY; /* Process args and tell the world that the torturer is on the job. */ @@ -898,6 +881,13 @@ static int __init lock_torture_init(void) firsterr = -EINVAL; goto unwind; } + + if (nwriters_stress == 0 && nreaders_stress == 0) { + pr_alert("lock-torture: must run at least one locking thread\n"); + firsterr = -EINVAL; + goto unwind; + } + if (cxt.cur_ops->init) cxt.cur_ops->init(); @@ -921,17 +911,19 @@ static int __init lock_torture_init(void) #endif /* Initialize the statistics so that each run gets its own numbers. */ + if (nwriters_stress) { + lock_is_write_held = 0; + cxt.lwsa = kmalloc(sizeof(*cxt.lwsa) * cxt.nrealwriters_stress, GFP_KERNEL); + if (cxt.lwsa == NULL) { + VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory"); + firsterr = -ENOMEM; + goto unwind; + } - lock_is_write_held = 0; - cxt.lwsa = kmalloc(sizeof(*cxt.lwsa) * cxt.nrealwriters_stress, GFP_KERNEL); - if (cxt.lwsa == NULL) { - VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory"); - firsterr = -ENOMEM; - goto unwind; - } - for (i = 0; i < cxt.nrealwriters_stress; i++) { - cxt.lwsa[i].n_lock_fail = 0; - cxt.lwsa[i].n_lock_acquired = 0; + for (i = 0; i < cxt.nrealwriters_stress; i++) { + cxt.lwsa[i].n_lock_fail = 0; + cxt.lwsa[i].n_lock_acquired = 0; + } } if (cxt.cur_ops->readlock) { @@ -948,19 +940,21 @@ static int __init lock_torture_init(void) cxt.nrealreaders_stress = cxt.nrealwriters_stress; } - lock_is_read_held = 0; - cxt.lrsa = kmalloc(sizeof(*cxt.lrsa) * cxt.nrealreaders_stress, GFP_KERNEL); - if (cxt.lrsa == NULL) { - VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory"); - firsterr = -ENOMEM; - kfree(cxt.lwsa); - cxt.lwsa = NULL; - goto unwind; - } - - for (i = 0; i < cxt.nrealreaders_stress; i++) { - cxt.lrsa[i].n_lock_fail = 0; - cxt.lrsa[i].n_lock_acquired = 0; + if (nreaders_stress) { + lock_is_read_held = 0; + cxt.lrsa = kmalloc(sizeof(*cxt.lrsa) * cxt.nrealreaders_stress, GFP_KERNEL); + if (cxt.lrsa == NULL) { + VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory"); + firsterr = -ENOMEM; + kfree(cxt.lwsa); + cxt.lwsa = NULL; + goto unwind; + } + + for (i = 0; i < cxt.nrealreaders_stress; i++) { + cxt.lrsa[i].n_lock_fail = 0; + cxt.lrsa[i].n_lock_acquired = 0; + } } } @@ -990,12 +984,14 @@ static int __init lock_torture_init(void) goto unwind; } - writer_tasks = kzalloc(cxt.nrealwriters_stress * sizeof(writer_tasks[0]), - GFP_KERNEL); - if (writer_tasks == NULL) { - VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory"); - firsterr = -ENOMEM; - goto unwind; + if (nwriters_stress) { + writer_tasks = kzalloc(cxt.nrealwriters_stress * sizeof(writer_tasks[0]), + GFP_KERNEL); + if (writer_tasks == NULL) { + VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory"); + firsterr = -ENOMEM; + goto unwind; + } } if (cxt.cur_ops->readlock) { diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 294294c..38ece03 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -170,7 +170,7 @@ static __always_inline void clear_pending_set_locked(struct qspinlock *lock) * @tail : The new queue tail code word * Return: The previous queue tail code word * - * xchg(lock, tail) + * xchg(lock, tail), which heads an address dependency * * p,*,* -> n,*,* ; prev = xchg(lock, node) */ @@ -409,13 +409,11 @@ queue: if (old & _Q_TAIL_MASK) { prev = decode_tail(old); /* - * The above xchg_tail() is also a load of @lock which generates, - * through decode_tail(), a pointer. - * - * The address dependency matches the RELEASE of xchg_tail() - * such that the access to @prev must happen after. + * The above xchg_tail() is also a load of @lock which + * generates, through decode_tail(), a pointer. The address + * dependency matches the RELEASE of xchg_tail() such that + * the subsequent access to @prev happens after. */ - smp_read_barrier_depends(); WRITE_ONCE(prev->next, node); diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 6f3dba6..65cc0cb 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1290,6 +1290,19 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state, return ret; } +static inline int __rt_mutex_slowtrylock(struct rt_mutex *lock) +{ + int ret = try_to_take_rt_mutex(lock, current, NULL); + + /* + * try_to_take_rt_mutex() sets the lock waiters bit + * unconditionally. Clean this up. + */ + fixup_rt_mutex_waiters(lock); + + return ret; +} + /* * Slow path try-lock function: */ @@ -1312,13 +1325,7 @@ static inline int rt_mutex_slowtrylock(struct rt_mutex *lock) */ raw_spin_lock_irqsave(&lock->wait_lock, flags); - ret = try_to_take_rt_mutex(lock, current, NULL); - - /* - * try_to_take_rt_mutex() sets the lock waiters bit - * unconditionally. Clean this up. - */ - fixup_rt_mutex_waiters(lock); + ret = __rt_mutex_slowtrylock(lock); raw_spin_unlock_irqrestore(&lock->wait_lock, flags); @@ -1505,6 +1512,11 @@ int __sched rt_mutex_futex_trylock(struct rt_mutex *lock) return rt_mutex_slowtrylock(lock); } +int __sched __rt_mutex_futex_trylock(struct rt_mutex *lock) +{ + return __rt_mutex_slowtrylock(lock); +} + /** * rt_mutex_timed_lock - lock a rt_mutex interruptible * the timeout structure is provided diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h index 124e98c..68686b3 100644 --- a/kernel/locking/rtmutex_common.h +++ b/kernel/locking/rtmutex_common.h @@ -148,6 +148,7 @@ extern bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock, struct rt_mutex_waiter *waiter); extern int rt_mutex_futex_trylock(struct rt_mutex *l); +extern int __rt_mutex_futex_trylock(struct rt_mutex *l); extern void rt_mutex_futex_unlock(struct rt_mutex *lock); extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock, diff --git a/kernel/locking/spinlock.c b/kernel/locking/spinlock.c index 1fd1a75..936f3d1 100644 --- a/kernel/locking/spinlock.c +++ b/kernel/locking/spinlock.c @@ -66,12 +66,8 @@ void __lockfunc __raw_##op##_lock(locktype##_t *lock) \ break; \ preempt_enable(); \ \ - if (!(lock)->break_lock) \ - (lock)->break_lock = 1; \ - while ((lock)->break_lock) \ - arch_##op##_relax(&lock->raw_lock); \ + arch_##op##_relax(&lock->raw_lock); \ } \ - (lock)->break_lock = 0; \ } \ \ unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock) \ @@ -86,12 +82,9 @@ unsigned long __lockfunc __raw_##op##_lock_irqsave(locktype##_t *lock) \ local_irq_restore(flags); \ preempt_enable(); \ \ - if (!(lock)->break_lock) \ - (lock)->break_lock = 1; \ - while ((lock)->break_lock) \ - arch_##op##_relax(&lock->raw_lock); \ + arch_##op##_relax(&lock->raw_lock); \ } \ - (lock)->break_lock = 0; \ + \ return flags; \ } \ \ |
