kernel/lockdep_proc.c

   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
  22 static 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
  38 static 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
  48 static void l_stop(struct seq_file *m, void *v)
  49 {
  50 }
  51
  52 static 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
  66 static 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
  80 static 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
 116 static const struct seq_operations lockdep_ops = {
 117         .start  = l_start,
 118         .next   = l_next,
 119         .stop   = l_stop,
 120         .show   = l_show,
 121 };
 122
 123 static 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
 138 static const struct file_operations proc_lockdep_operations = {
 139         .open           = lockdep_open,
 140         .read           = seq_read,
 141         .llseek         = seq_lseek,
 142         .release        = seq_release,
 143 };
 144
 145 static 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
 185 static 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
 317 static int lockdep_stats_open(struct inode *inode, struct file *file)
 318 {
 319         return single_open(file, lockdep_stats_show, NULL);
 320 }
 321
 322 static const 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
 329 static 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