linux/kernel/lockdep_proc.c
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   1/*
   2 * kernel/lockdep_proc.c
   3 *
   4 * Runtime locking correctness validator
   5 *
   6 * Started by Ingo Molnar:
   7 *
   8 *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
   9 *
  10 * Code for /proc/lockdep and /proc/lockdep_stats:
  11 *
  12 */
  13#include <linux/sched.h>
  14#include <linux/module.h>
  15#include <linux/proc_fs.h>
  16#include <linux/seq_file.h>
  17#include <linux/kallsyms.h>
  18#include <linux/debug_locks.h>
  19
  20#include "lockdep_internals.h"
  21
  22static void *l_next(struct seq_file *m, void *v, loff_t *pos)
  23{
  24        struct lock_class *class = v;
  25
  26        (*pos)++;
  27
  28        if (class->lock_entry.next != &all_lock_classes)
  29                class = list_entry(class->lock_entry.next, struct lock_class,
  30                                  lock_entry);
  31        else
  32                class = NULL;
  33        m->private = class;
  34
  35        return class;
  36}
  37
  38static void *l_start(struct seq_file *m, loff_t *pos)
  39{
  40        struct lock_class *class = m->private;
  41
  42        if (&class->lock_entry == all_lock_classes.next)
  43                seq_printf(m, "all lock classes:\n");
  44
  45        return class;
  46}
  47
  48static void l_stop(struct seq_file *m, void *v)
  49{
  50}
  51
  52static unsigned long count_forward_deps(struct lock_class *class)
  53{
  54        struct lock_list *entry;
  55        unsigned long ret = 1;
  56
  57        /*
  58         * Recurse this class's dependency list:
  59         */
  60        list_for_each_entry(entry, &class->locks_after, entry)
  61                ret += count_forward_deps(entry->class);
  62
  63        return ret;
  64}
  65
  66static unsigned long count_backward_deps(struct lock_class *class)
  67{
  68        struct lock_list *entry;
  69        unsigned long ret = 1;
  70
  71        /*
  72         * Recurse this class's dependency list:
  73         */
  74        list_for_each_entry(entry, &class->locks_before, entry)
  75                ret += count_backward_deps(entry->class);
  76
  77        return ret;
  78}
  79
  80static int l_show(struct seq_file *m, void *v)
  81{
  82        unsigned long nr_forward_deps, nr_backward_deps;
  83        struct lock_class *class = m->private;
  84        char str[128], c1, c2, c3, c4;
  85        const char *name;
  86
  87        seq_printf(m, "%p", class->key);
  88#ifdef CONFIG_DEBUG_LOCKDEP
  89        seq_printf(m, " OPS:%8ld", class->ops);
  90#endif
  91        nr_forward_deps = count_forward_deps(class);
  92        seq_printf(m, " FD:%5ld", nr_forward_deps);
  93
  94        nr_backward_deps = count_backward_deps(class);
  95        seq_printf(m, " BD:%5ld", nr_backward_deps);
  96
  97        get_usage_chars(class, &c1, &c2, &c3, &c4);
  98        seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
  99
 100        name = class->name;
 101        if (!name) {
 102                name = __get_key_name(class->key, str);
 103                seq_printf(m, ": %s", name);
 104        } else{
 105                seq_printf(m, ": %s", name);
 106                if (class->name_version > 1)
 107                        seq_printf(m, "#%d", class->name_version);
 108                if (class->subclass)
 109                        seq_printf(m, "/%d", class->subclass);
 110        }
 111        seq_puts(m, "\n");
 112
 113        return 0;
 114}
 115
 116static struct seq_operations lockdep_ops = {
 117        .start  = l_start,
 118        .next   = l_next,
 119        .stop   = l_stop,
 120        .show   = l_show,
 121};
 122
 123static int lockdep_open(struct inode *inode, struct file *file)
 124{
 125        int res = seq_open(file, &lockdep_ops);
 126        if (!res) {
 127                struct seq_file *m = file->private_data;
 128
 129                if (!list_empty(&all_lock_classes))
 130                        m->private = list_entry(all_lock_classes.next,
 131                                        struct lock_class, lock_entry);
 132                else
 133                        m->private = NULL;
 134        }
 135        return res;
 136}
 137
 138static struct file_operations proc_lockdep_operations = {
 139        .open           = lockdep_open,
 140        .read           = seq_read,
 141        .llseek         = seq_lseek,
 142        .release        = seq_release,
 143};
 144
 145static void lockdep_stats_debug_show(struct seq_file *m)
 146{
 147#ifdef CONFIG_DEBUG_LOCKDEP
 148        unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
 149                     hi2 = debug_atomic_read(&hardirqs_off_events),
 150                     hr1 = debug_atomic_read(&redundant_hardirqs_on),
 151                     hr2 = debug_atomic_read(&redundant_hardirqs_off),
 152                     si1 = debug_atomic_read(&softirqs_on_events),
 153                     si2 = debug_atomic_read(&softirqs_off_events),
 154                     sr1 = debug_atomic_read(&redundant_softirqs_on),
 155                     sr2 = debug_atomic_read(&redundant_softirqs_off);
 156
 157        seq_printf(m, " chain lookup misses:           %11u\n",
 158                debug_atomic_read(&chain_lookup_misses));
 159        seq_printf(m, " chain lookup hits:             %11u\n",
 160                debug_atomic_read(&chain_lookup_hits));
 161        seq_printf(m, " cyclic checks:                 %11u\n",
 162                debug_atomic_read(&nr_cyclic_checks));
 163        seq_printf(m, " cyclic-check recursions:       %11u\n",
 164                debug_atomic_read(&nr_cyclic_check_recursions));
 165        seq_printf(m, " find-mask forwards checks:     %11u\n",
 166                debug_atomic_read(&nr_find_usage_forwards_checks));
 167        seq_printf(m, " find-mask forwards recursions: %11u\n",
 168                debug_atomic_read(&nr_find_usage_forwards_recursions));
 169        seq_printf(m, " find-mask backwards checks:    %11u\n",
 170                debug_atomic_read(&nr_find_usage_backwards_checks));
 171        seq_printf(m, " find-mask backwards recursions:%11u\n",
 172                debug_atomic_read(&nr_find_usage_backwards_recursions));
 173
 174        seq_printf(m, " hardirq on events:             %11u\n", hi1);
 175        seq_printf(m, " hardirq off events:            %11u\n", hi2);
 176        seq_printf(m, " redundant hardirq ons:         %11u\n", hr1);
 177        seq_printf(m, " redundant hardirq offs:        %11u\n", hr2);
 178        seq_printf(m, " softirq on events:             %11u\n", si1);
 179        seq_printf(m, " softirq off events:            %11u\n", si2);
 180        seq_printf(m, " redundant softirq ons:         %11u\n", sr1);
 181        seq_printf(m, " redundant softirq offs:        %11u\n", sr2);
 182#endif
 183}
 184
 185static int lockdep_stats_show(struct seq_file *m, void *v)
 186{
 187        struct lock_class *class;
 188        unsigned long nr_unused = 0, nr_uncategorized = 0,
 189                      nr_irq_safe = 0, nr_irq_unsafe = 0,
 190                      nr_softirq_safe = 0, nr_softirq_unsafe = 0,
 191                      nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
 192                      nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
 193                      nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
 194                      nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
 195                      sum_forward_deps = 0, factor = 0;
 196
 197        list_for_each_entry(class, &all_lock_classes, lock_entry) {
 198
 199                if (class->usage_mask == 0)
 200                        nr_unused++;
 201                if (class->usage_mask == LOCKF_USED)
 202                        nr_uncategorized++;
 203                if (class->usage_mask & LOCKF_USED_IN_IRQ)
 204                        nr_irq_safe++;
 205                if (class->usage_mask & LOCKF_ENABLED_IRQS)
 206                        nr_irq_unsafe++;
 207                if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
 208                        nr_softirq_safe++;
 209                if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
 210                        nr_softirq_unsafe++;
 211                if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
 212                        nr_hardirq_safe++;
 213                if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
 214                        nr_hardirq_unsafe++;
 215                if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
 216                        nr_irq_read_safe++;
 217                if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
 218                        nr_irq_read_unsafe++;
 219                if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
 220                        nr_softirq_read_safe++;
 221                if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
 222                        nr_softirq_read_unsafe++;
 223                if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
 224                        nr_hardirq_read_safe++;
 225                if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
 226                        nr_hardirq_read_unsafe++;
 227
 228                sum_forward_deps += count_forward_deps(class);
 229        }
 230#ifdef CONFIG_LOCKDEP_DEBUG
 231        DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
 232#endif
 233        seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
 234                        nr_lock_classes, MAX_LOCKDEP_KEYS);
 235        seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
 236                        nr_list_entries, MAX_LOCKDEP_ENTRIES);
 237        seq_printf(m, " indirect dependencies:         %11lu\n",
 238                        sum_forward_deps);
 239
 240        /*
 241         * Total number of dependencies:
 242         *
 243         * All irq-safe locks may nest inside irq-unsafe locks,
 244         * plus all the other known dependencies:
 245         */
 246        seq_printf(m, " all direct dependencies:       %11lu\n",
 247                        nr_irq_unsafe * nr_irq_safe +
 248                        nr_hardirq_unsafe * nr_hardirq_safe +
 249                        nr_list_entries);
 250
 251        /*
 252         * Estimated factor between direct and indirect
 253         * dependencies:
 254         */
 255        if (nr_list_entries)
 256                factor = sum_forward_deps / nr_list_entries;
 257
 258        seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
 259                        nr_lock_chains, MAX_LOCKDEP_CHAINS);
 260
 261#ifdef CONFIG_TRACE_IRQFLAGS
 262        seq_printf(m, " in-hardirq chains:             %11u\n",
 263                        nr_hardirq_chains);
 264        seq_printf(m, " in-softirq chains:             %11u\n",
 265                        nr_softirq_chains);
 266#endif
 267        seq_printf(m, " in-process chains:             %11u\n",
 268                        nr_process_chains);
 269        seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
 270                        nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
 271        seq_printf(m, " combined max dependencies:     %11u\n",
 272                        (nr_hardirq_chains + 1) *
 273                        (nr_softirq_chains + 1) *
 274                        (nr_process_chains + 1)
 275        );
 276        seq_printf(m, " hardirq-safe locks:            %11lu\n",
 277                        nr_hardirq_safe);
 278        seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
 279                        nr_hardirq_unsafe);
 280        seq_printf(m, " softirq-safe locks:            %11lu\n",
 281                        nr_softirq_safe);
 282        seq_printf(m, " softirq-unsafe locks:          %11lu\n",
 283                        nr_softirq_unsafe);
 284        seq_printf(m, " irq-safe locks:                %11lu\n",
 285                        nr_irq_safe);
 286        seq_printf(m, " irq-unsafe locks:              %11lu\n",
 287                        nr_irq_unsafe);
 288
 289        seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
 290                        nr_hardirq_read_safe);
 291        seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
 292                        nr_hardirq_read_unsafe);
 293        seq_printf(m, " softirq-read-safe locks:       %11lu\n",
 294                        nr_softirq_read_safe);
 295        seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
 296                        nr_softirq_read_unsafe);
 297        seq_printf(m, " irq-read-safe locks:           %11lu\n",
 298                        nr_irq_read_safe);
 299        seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
 300                        nr_irq_read_unsafe);
 301
 302        seq_printf(m, " uncategorized locks:           %11lu\n",
 303                        nr_uncategorized);
 304        seq_printf(m, " unused locks:                  %11lu\n",
 305                        nr_unused);
 306        seq_printf(m, " max locking depth:             %11u\n",
 307                        max_lockdep_depth);
 308        seq_printf(m, " max recursion depth:           %11u\n",
 309                        max_recursion_depth);
 310        lockdep_stats_debug_show(m);
 311        seq_printf(m, " debug_locks:                   %11u\n",
 312                        debug_locks);
 313
 314        return 0;
 315}
 316
 317static int lockdep_stats_open(struct inode *inode, struct file *file)
 318{
 319        return single_open(file, lockdep_stats_show, NULL);
 320}
 321
 322static struct file_operations proc_lockdep_stats_operations = {
 323        .open           = lockdep_stats_open,
 324        .read           = seq_read,
 325        .llseek         = seq_lseek,
 326        .release        = seq_release,
 327};
 328
 329static int __init lockdep_proc_init(void)
 330{
 331        struct proc_dir_entry *entry;
 332
 333        entry = create_proc_entry("lockdep", S_IRUSR, NULL);
 334        if (entry)
 335                entry->proc_fops = &proc_lockdep_operations;
 336
 337        entry = create_proc_entry("lockdep_stats", S_IRUSR, NULL);
 338        if (entry)
 339                entry->proc_fops = &proc_lockdep_stats_operations;
 340
 341        return 0;
 342}
 343
 344__initcall(lockdep_proc_init);
 345
 346