diff options
Diffstat (limited to 'kernel/locking/lockdep_proc.c')
| -rw-r--r-- | kernel/locking/lockdep_proc.c | 730 |
1 files changed, 730 insertions, 0 deletions
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c new file mode 100644 index 000000000..15fdc7fa5 --- /dev/null +++ b/kernel/locking/lockdep_proc.c @@ -0,0 +1,730 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * kernel/lockdep_proc.c + * + * Runtime locking correctness validator + * + * Started by Ingo Molnar: + * + * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> + * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra + * + * Code for /proc/lockdep and /proc/lockdep_stats: + * + */ +#include <linux/export.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <linux/kallsyms.h> +#include <linux/debug_locks.h> +#include <linux/vmalloc.h> +#include <linux/sort.h> +#include <linux/uaccess.h> +#include <asm/div64.h> + +#include "lockdep_internals.h" + +/* + * Since iteration of lock_classes is done without holding the lockdep lock, + * it is not safe to iterate all_lock_classes list directly as the iteration + * may branch off to free_lock_classes or the zapped list. Iteration is done + * directly on the lock_classes array by checking the lock_classes_in_use + * bitmap and max_lock_class_idx. + */ +#define iterate_lock_classes(idx, class) \ + for (idx = 0, class = lock_classes; idx <= max_lock_class_idx; \ + idx++, class++) + +static void *l_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct lock_class *class = v; + + ++class; + *pos = class - lock_classes; + return (*pos > max_lock_class_idx) ? NULL : class; +} + +static void *l_start(struct seq_file *m, loff_t *pos) +{ + unsigned long idx = *pos; + + if (idx > max_lock_class_idx) + return NULL; + return lock_classes + idx; +} + +static void l_stop(struct seq_file *m, void *v) +{ +} + +static void print_name(struct seq_file *m, struct lock_class *class) +{ + char str[KSYM_NAME_LEN]; + const char *name = class->name; + + if (!name) { + name = __get_key_name(class->key, str); + seq_printf(m, "%s", name); + } else{ + seq_printf(m, "%s", name); + if (class->name_version > 1) + seq_printf(m, "#%d", class->name_version); + if (class->subclass) + seq_printf(m, "/%d", class->subclass); + } +} + +static int l_show(struct seq_file *m, void *v) +{ + struct lock_class *class = v; + struct lock_list *entry; + char usage[LOCK_USAGE_CHARS]; + int idx = class - lock_classes; + + if (v == lock_classes) + seq_printf(m, "all lock classes:\n"); + + if (!test_bit(idx, lock_classes_in_use)) + return 0; + + seq_printf(m, "%p", class->key); +#ifdef CONFIG_DEBUG_LOCKDEP + seq_printf(m, " OPS:%8ld", debug_class_ops_read(class)); +#endif + if (IS_ENABLED(CONFIG_PROVE_LOCKING)) { + seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class)); + seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class)); + + get_usage_chars(class, usage); + seq_printf(m, " %s", usage); + } + + seq_printf(m, ": "); + print_name(m, class); + seq_puts(m, "\n"); + + if (IS_ENABLED(CONFIG_PROVE_LOCKING)) { + list_for_each_entry(entry, &class->locks_after, entry) { + if (entry->distance == 1) { + seq_printf(m, " -> [%p] ", entry->class->key); + print_name(m, entry->class); + seq_puts(m, "\n"); + } + } + seq_puts(m, "\n"); + } + + return 0; +} + +static const struct seq_operations lockdep_ops = { + .start = l_start, + .next = l_next, + .stop = l_stop, + .show = l_show, +}; + +#ifdef CONFIG_PROVE_LOCKING +static void *lc_start(struct seq_file *m, loff_t *pos) +{ + if (*pos < 0) + return NULL; + + if (*pos == 0) + return SEQ_START_TOKEN; + + return lock_chains + (*pos - 1); +} + +static void *lc_next(struct seq_file *m, void *v, loff_t *pos) +{ + *pos = lockdep_next_lockchain(*pos - 1) + 1; + return lc_start(m, pos); +} + +static void lc_stop(struct seq_file *m, void *v) +{ +} + +static int lc_show(struct seq_file *m, void *v) +{ + struct lock_chain *chain = v; + struct lock_class *class; + int i; + static const char * const irq_strs[] = { + [0] = "0", + [LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq", + [LOCK_CHAIN_SOFTIRQ_CONTEXT] = "softirq", + [LOCK_CHAIN_SOFTIRQ_CONTEXT| + LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq|softirq", + }; + + if (v == SEQ_START_TOKEN) { + if (!nr_free_chain_hlocks) + seq_printf(m, "(buggered) "); + seq_printf(m, "all lock chains:\n"); + return 0; + } + + seq_printf(m, "irq_context: %s\n", irq_strs[chain->irq_context]); + + for (i = 0; i < chain->depth; i++) { + class = lock_chain_get_class(chain, i); + if (!class->key) + continue; + + seq_printf(m, "[%p] ", class->key); + print_name(m, class); + seq_puts(m, "\n"); + } + seq_puts(m, "\n"); + + return 0; +} + +static const struct seq_operations lockdep_chains_ops = { + .start = lc_start, + .next = lc_next, + .stop = lc_stop, + .show = lc_show, +}; +#endif /* CONFIG_PROVE_LOCKING */ + +static void lockdep_stats_debug_show(struct seq_file *m) +{ +#ifdef CONFIG_DEBUG_LOCKDEP + unsigned long long hi1 = debug_atomic_read(hardirqs_on_events), + hi2 = debug_atomic_read(hardirqs_off_events), + hr1 = debug_atomic_read(redundant_hardirqs_on), + hr2 = debug_atomic_read(redundant_hardirqs_off), + si1 = debug_atomic_read(softirqs_on_events), + si2 = debug_atomic_read(softirqs_off_events), + sr1 = debug_atomic_read(redundant_softirqs_on), + sr2 = debug_atomic_read(redundant_softirqs_off); + + seq_printf(m, " chain lookup misses: %11llu\n", + debug_atomic_read(chain_lookup_misses)); + seq_printf(m, " chain lookup hits: %11llu\n", + debug_atomic_read(chain_lookup_hits)); + seq_printf(m, " cyclic checks: %11llu\n", + debug_atomic_read(nr_cyclic_checks)); + seq_printf(m, " redundant checks: %11llu\n", + debug_atomic_read(nr_redundant_checks)); + seq_printf(m, " redundant links: %11llu\n", + debug_atomic_read(nr_redundant)); + seq_printf(m, " find-mask forwards checks: %11llu\n", + debug_atomic_read(nr_find_usage_forwards_checks)); + seq_printf(m, " find-mask backwards checks: %11llu\n", + debug_atomic_read(nr_find_usage_backwards_checks)); + + seq_printf(m, " hardirq on events: %11llu\n", hi1); + seq_printf(m, " hardirq off events: %11llu\n", hi2); + seq_printf(m, " redundant hardirq ons: %11llu\n", hr1); + seq_printf(m, " redundant hardirq offs: %11llu\n", hr2); + seq_printf(m, " softirq on events: %11llu\n", si1); + seq_printf(m, " softirq off events: %11llu\n", si2); + seq_printf(m, " redundant softirq ons: %11llu\n", sr1); + seq_printf(m, " redundant softirq offs: %11llu\n", sr2); +#endif +} + +static int lockdep_stats_show(struct seq_file *m, void *v) +{ + unsigned long nr_unused = 0, nr_uncategorized = 0, + nr_irq_safe = 0, nr_irq_unsafe = 0, + nr_softirq_safe = 0, nr_softirq_unsafe = 0, + nr_hardirq_safe = 0, nr_hardirq_unsafe = 0, + nr_irq_read_safe = 0, nr_irq_read_unsafe = 0, + nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0, + nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0, + sum_forward_deps = 0; + +#ifdef CONFIG_PROVE_LOCKING + struct lock_class *class; + unsigned long idx; + + iterate_lock_classes(idx, class) { + if (!test_bit(idx, lock_classes_in_use)) + continue; + + if (class->usage_mask == 0) + nr_unused++; + if (class->usage_mask == LOCKF_USED) + nr_uncategorized++; + if (class->usage_mask & LOCKF_USED_IN_IRQ) + nr_irq_safe++; + if (class->usage_mask & LOCKF_ENABLED_IRQ) + nr_irq_unsafe++; + if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ) + nr_softirq_safe++; + if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ) + nr_softirq_unsafe++; + if (class->usage_mask & LOCKF_USED_IN_HARDIRQ) + nr_hardirq_safe++; + if (class->usage_mask & LOCKF_ENABLED_HARDIRQ) + nr_hardirq_unsafe++; + if (class->usage_mask & LOCKF_USED_IN_IRQ_READ) + nr_irq_read_safe++; + if (class->usage_mask & LOCKF_ENABLED_IRQ_READ) + nr_irq_read_unsafe++; + if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) + nr_softirq_read_safe++; + if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ) + nr_softirq_read_unsafe++; + if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) + nr_hardirq_read_safe++; + if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ) + nr_hardirq_read_unsafe++; + + sum_forward_deps += lockdep_count_forward_deps(class); + } + +#ifdef CONFIG_DEBUG_LOCKDEP + DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused); +#endif + +#endif + seq_printf(m, " lock-classes: %11lu [max: %lu]\n", + nr_lock_classes, MAX_LOCKDEP_KEYS); + seq_printf(m, " direct dependencies: %11lu [max: %lu]\n", + nr_list_entries, MAX_LOCKDEP_ENTRIES); + seq_printf(m, " indirect dependencies: %11lu\n", + sum_forward_deps); + + /* + * Total number of dependencies: + * + * All irq-safe locks may nest inside irq-unsafe locks, + * plus all the other known dependencies: + */ + seq_printf(m, " all direct dependencies: %11lu\n", + nr_irq_unsafe * nr_irq_safe + + nr_hardirq_unsafe * nr_hardirq_safe + + nr_list_entries); + +#ifdef CONFIG_PROVE_LOCKING + seq_printf(m, " dependency chains: %11lu [max: %lu]\n", + lock_chain_count(), MAX_LOCKDEP_CHAINS); + seq_printf(m, " dependency chain hlocks used: %11lu [max: %lu]\n", + MAX_LOCKDEP_CHAIN_HLOCKS - + (nr_free_chain_hlocks + nr_lost_chain_hlocks), + MAX_LOCKDEP_CHAIN_HLOCKS); + seq_printf(m, " dependency chain hlocks lost: %11u\n", + nr_lost_chain_hlocks); +#endif + +#ifdef CONFIG_TRACE_IRQFLAGS + seq_printf(m, " in-hardirq chains: %11u\n", + nr_hardirq_chains); + seq_printf(m, " in-softirq chains: %11u\n", + nr_softirq_chains); +#endif + seq_printf(m, " in-process chains: %11u\n", + nr_process_chains); + seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n", + nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES); +#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) + seq_printf(m, " number of stack traces: %11llu\n", + lockdep_stack_trace_count()); + seq_printf(m, " number of stack hash chains: %11llu\n", + lockdep_stack_hash_count()); +#endif + seq_printf(m, " combined max dependencies: %11u\n", + (nr_hardirq_chains + 1) * + (nr_softirq_chains + 1) * + (nr_process_chains + 1) + ); + seq_printf(m, " hardirq-safe locks: %11lu\n", + nr_hardirq_safe); + seq_printf(m, " hardirq-unsafe locks: %11lu\n", + nr_hardirq_unsafe); + seq_printf(m, " softirq-safe locks: %11lu\n", + nr_softirq_safe); + seq_printf(m, " softirq-unsafe locks: %11lu\n", + nr_softirq_unsafe); + seq_printf(m, " irq-safe locks: %11lu\n", + nr_irq_safe); + seq_printf(m, " irq-unsafe locks: %11lu\n", + nr_irq_unsafe); + + seq_printf(m, " hardirq-read-safe locks: %11lu\n", + nr_hardirq_read_safe); + seq_printf(m, " hardirq-read-unsafe locks: %11lu\n", + nr_hardirq_read_unsafe); + seq_printf(m, " softirq-read-safe locks: %11lu\n", + nr_softirq_read_safe); + seq_printf(m, " softirq-read-unsafe locks: %11lu\n", + nr_softirq_read_unsafe); + seq_printf(m, " irq-read-safe locks: %11lu\n", + nr_irq_read_safe); + seq_printf(m, " irq-read-unsafe locks: %11lu\n", + nr_irq_read_unsafe); + + seq_printf(m, " uncategorized locks: %11lu\n", + nr_uncategorized); + seq_printf(m, " unused locks: %11lu\n", + nr_unused); + seq_printf(m, " max locking depth: %11u\n", + max_lockdep_depth); +#ifdef CONFIG_PROVE_LOCKING + seq_printf(m, " max bfs queue depth: %11u\n", + max_bfs_queue_depth); +#endif + seq_printf(m, " max lock class index: %11lu\n", + max_lock_class_idx); + lockdep_stats_debug_show(m); + seq_printf(m, " debug_locks: %11u\n", + debug_locks); + + /* + * Zapped classes and lockdep data buffers reuse statistics. + */ + seq_puts(m, "\n"); + seq_printf(m, " zapped classes: %11lu\n", + nr_zapped_classes); +#ifdef CONFIG_PROVE_LOCKING + seq_printf(m, " zapped lock chains: %11lu\n", + nr_zapped_lock_chains); + seq_printf(m, " large chain blocks: %11u\n", + nr_large_chain_blocks); +#endif + return 0; +} + +#ifdef CONFIG_LOCK_STAT + +struct lock_stat_data { + struct lock_class *class; + struct lock_class_stats stats; +}; + +struct lock_stat_seq { + struct lock_stat_data *iter_end; + struct lock_stat_data stats[MAX_LOCKDEP_KEYS]; +}; + +/* + * sort on absolute number of contentions + */ +static int lock_stat_cmp(const void *l, const void *r) +{ + const struct lock_stat_data *dl = l, *dr = r; + unsigned long nl, nr; + + nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr; + nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr; + + return nr - nl; +} + +static void seq_line(struct seq_file *m, char c, int offset, int length) +{ + int i; + + for (i = 0; i < offset; i++) + seq_puts(m, " "); + for (i = 0; i < length; i++) + seq_printf(m, "%c", c); + seq_puts(m, "\n"); +} + +static void snprint_time(char *buf, size_t bufsiz, s64 nr) +{ + s64 div; + s32 rem; + + nr += 5; /* for display rounding */ + div = div_s64_rem(nr, 1000, &rem); + snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10); +} + +static void seq_time(struct seq_file *m, s64 time) +{ + char num[15]; + + snprint_time(num, sizeof(num), time); + seq_printf(m, " %14s", num); +} + +static void seq_lock_time(struct seq_file *m, struct lock_time *lt) +{ + seq_printf(m, "%14lu", lt->nr); + seq_time(m, lt->min); + seq_time(m, lt->max); + seq_time(m, lt->total); + seq_time(m, lt->nr ? div64_u64(lt->total, lt->nr) : 0); +} + +static void seq_stats(struct seq_file *m, struct lock_stat_data *data) +{ + const struct lockdep_subclass_key *ckey; + struct lock_class_stats *stats; + struct lock_class *class; + const char *cname; + int i, namelen; + char name[39]; + + class = data->class; + stats = &data->stats; + + namelen = 38; + if (class->name_version > 1) + namelen -= 2; /* XXX truncates versions > 9 */ + if (class->subclass) + namelen -= 2; + + rcu_read_lock_sched(); + cname = rcu_dereference_sched(class->name); + ckey = rcu_dereference_sched(class->key); + + if (!cname && !ckey) { + rcu_read_unlock_sched(); + return; + + } else if (!cname) { + char str[KSYM_NAME_LEN]; + const char *key_name; + + key_name = __get_key_name(ckey, str); + snprintf(name, namelen, "%s", key_name); + } else { + snprintf(name, namelen, "%s", cname); + } + rcu_read_unlock_sched(); + + namelen = strlen(name); + if (class->name_version > 1) { + snprintf(name+namelen, 3, "#%d", class->name_version); + namelen += 2; + } + if (class->subclass) { + snprintf(name+namelen, 3, "/%d", class->subclass); + namelen += 2; + } + + if (stats->write_holdtime.nr) { + if (stats->read_holdtime.nr) + seq_printf(m, "%38s-W:", name); + else + seq_printf(m, "%40s:", name); + + seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]); + seq_lock_time(m, &stats->write_waittime); + seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]); + seq_lock_time(m, &stats->write_holdtime); + seq_puts(m, "\n"); + } + + if (stats->read_holdtime.nr) { + seq_printf(m, "%38s-R:", name); + seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]); + seq_lock_time(m, &stats->read_waittime); + seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]); + seq_lock_time(m, &stats->read_holdtime); + seq_puts(m, "\n"); + } + + if (stats->read_waittime.nr + stats->write_waittime.nr == 0) + return; + + if (stats->read_holdtime.nr) + namelen += 2; + + for (i = 0; i < LOCKSTAT_POINTS; i++) { + char ip[32]; + + if (class->contention_point[i] == 0) + break; + + if (!i) + seq_line(m, '-', 40-namelen, namelen); + + snprintf(ip, sizeof(ip), "[<%p>]", + (void *)class->contention_point[i]); + seq_printf(m, "%40s %14lu %29s %pS\n", + name, stats->contention_point[i], + ip, (void *)class->contention_point[i]); + } + for (i = 0; i < LOCKSTAT_POINTS; i++) { + char ip[32]; + + if (class->contending_point[i] == 0) + break; + + if (!i) + seq_line(m, '-', 40-namelen, namelen); + + snprintf(ip, sizeof(ip), "[<%p>]", + (void *)class->contending_point[i]); + seq_printf(m, "%40s %14lu %29s %pS\n", + name, stats->contending_point[i], + ip, (void *)class->contending_point[i]); + } + if (i) { + seq_puts(m, "\n"); + seq_line(m, '.', 0, 40 + 1 + 12 * (14 + 1)); + seq_puts(m, "\n"); + } +} + +static void seq_header(struct seq_file *m) +{ + seq_puts(m, "lock_stat version 0.4\n"); + + if (unlikely(!debug_locks)) + seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n"); + + seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1)); + seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s %14s " + "%14s %14s\n", + "class name", + "con-bounces", + "contentions", + "waittime-min", + "waittime-max", + "waittime-total", + "waittime-avg", + "acq-bounces", + "acquisitions", + "holdtime-min", + "holdtime-max", + "holdtime-total", + "holdtime-avg"); + seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1)); + seq_printf(m, "\n"); +} + +static void *ls_start(struct seq_file *m, loff_t *pos) +{ + struct lock_stat_seq *data = m->private; + struct lock_stat_data *iter; + + if (*pos == 0) + return SEQ_START_TOKEN; + + iter = data->stats + (*pos - 1); + if (iter >= data->iter_end) + iter = NULL; + + return iter; +} + +static void *ls_next(struct seq_file *m, void *v, loff_t *pos) +{ + (*pos)++; + return ls_start(m, pos); +} + +static void ls_stop(struct seq_file *m, void *v) +{ +} + +static int ls_show(struct seq_file *m, void *v) +{ + if (v == SEQ_START_TOKEN) + seq_header(m); + else + seq_stats(m, v); + + return 0; +} + +static const struct seq_operations lockstat_ops = { + .start = ls_start, + .next = ls_next, + .stop = ls_stop, + .show = ls_show, +}; + +static int lock_stat_open(struct inode *inode, struct file *file) +{ + int res; + struct lock_class *class; + struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq)); + + if (!data) + return -ENOMEM; + + res = seq_open(file, &lockstat_ops); + if (!res) { + struct lock_stat_data *iter = data->stats; + struct seq_file *m = file->private_data; + unsigned long idx; + + iterate_lock_classes(idx, class) { + if (!test_bit(idx, lock_classes_in_use)) + continue; + iter->class = class; + iter->stats = lock_stats(class); + iter++; + } + + data->iter_end = iter; + + sort(data->stats, data->iter_end - data->stats, + sizeof(struct lock_stat_data), + lock_stat_cmp, NULL); + + m->private = data; + } else + vfree(data); + + return res; +} + +static ssize_t lock_stat_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct lock_class *class; + unsigned long idx; + char c; + + if (count) { + if (get_user(c, buf)) + return -EFAULT; + + if (c != '0') + return count; + + iterate_lock_classes(idx, class) { + if (!test_bit(idx, lock_classes_in_use)) + continue; + clear_lock_stats(class); + } + } + return count; +} + +static int lock_stat_release(struct inode *inode, struct file *file) +{ + struct seq_file *seq = file->private_data; + + vfree(seq->private); + return seq_release(inode, file); +} + +static const struct proc_ops lock_stat_proc_ops = { + .proc_open = lock_stat_open, + .proc_write = lock_stat_write, + .proc_read = seq_read, + .proc_lseek = seq_lseek, + .proc_release = lock_stat_release, +}; +#endif /* CONFIG_LOCK_STAT */ + +static int __init lockdep_proc_init(void) +{ + proc_create_seq("lockdep", S_IRUSR, NULL, &lockdep_ops); +#ifdef CONFIG_PROVE_LOCKING + proc_create_seq("lockdep_chains", S_IRUSR, NULL, &lockdep_chains_ops); +#endif + proc_create_single("lockdep_stats", S_IRUSR, NULL, lockdep_stats_show); +#ifdef CONFIG_LOCK_STAT + proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL, &lock_stat_proc_ops); +#endif + + return 0; +} + +__initcall(lockdep_proc_init); + |