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 void print_name(struct seq_file *m, struct lock_class *class)
  81 {
  82         char str[128];
  83         const char *name = class->name;
  84
  85         if (!name) {
  86                 name = __get_key_name(class->key, str);
  87                 seq_printf(m, "%s", name);
  88         } else{
  89                 seq_printf(m, "%s", name);
  90                 if (class->name_version > 1)
  91                         seq_printf(m, "#%d", class->name_version);
  92                 if (class->subclass)
  93                         seq_printf(m, "/%d", class->subclass);
  94         }
  95 }
  96
  97 static int l_show(struct seq_file *m, void *v)
  98 {
  99         unsigned long nr_forward_deps, nr_backward_deps;
 100         struct lock_class *class = m->private;
 101         struct lock_list *entry;
 102         char c1, c2, c3, c4;
 103
 104         seq_printf(m, "%p", class->key);
 105 #ifdef CONFIG_DEBUG_LOCKDEP
 106         seq_printf(m, " OPS:%8ld", class->ops);
 107 #endif
 108         nr_forward_deps = count_forward_deps(class);
 109         seq_printf(m, " FD:%5ld", nr_forward_deps);
 110
 111         nr_backward_deps = count_backward_deps(class);
 112         seq_printf(m, " BD:%5ld", nr_backward_deps);
 113
 114         get_usage_chars(class, &c1, &c2, &c3, &c4);
 115         seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
 116
 117         seq_printf(m, ": ");
 118         print_name(m, class);
 119         seq_puts(m, "\n");
 120
 121         list_for_each_entry(entry, &class->locks_after, entry) {
 122                 if (entry->distance == 1) {
 123                         seq_printf(m, " -> [%p] ", entry->class);
 124                         print_name(m, entry->class);
 125                         seq_puts(m, "\n");
 126                 }
 127         }
 128         seq_puts(m, "\n");
 129
 130         return 0;
 131 }
 132
 133 static const struct seq_operations lockdep_ops = {
 134         .start  = l_start,
 135         .next   = l_next,
 136         .stop   = l_stop,
 137         .show   = l_show,
 138 };
 139
 140 static int lockdep_open(struct inode *inode, struct file *file)
 141 {
 142         int res = seq_open(file, &lockdep_ops);
 143         if (!res) {
 144                 struct seq_file *m = file->private_data;
 145
 146                 if (!list_empty(&all_lock_classes))
 147                         m->private = list_entry(all_lock_classes.next,
 148                                         struct lock_class, lock_entry);
 149                 else
 150                         m->private = NULL;
 151         }
 152         return res;
 153 }
 154
 155 static const struct file_operations proc_lockdep_operations = {
 156         .open           = lockdep_open,
 157         .read           = seq_read,
 158         .llseek         = seq_lseek,
 159         .release        = seq_release,
 160 };
 161
 162 static void lockdep_stats_debug_show(struct seq_file *m)
 163 {
 164 #ifdef CONFIG_DEBUG_LOCKDEP
 165         unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
 166                      hi2 = debug_atomic_read(&hardirqs_off_events),
 167                      hr1 = debug_atomic_read(&redundant_hardirqs_on),
 168                      hr2 = debug_atomic_read(&redundant_hardirqs_off),
 169                      si1 = debug_atomic_read(&softirqs_on_events),
 170                      si2 = debug_atomic_read(&softirqs_off_events),
 171                      sr1 = debug_atomic_read(&redundant_softirqs_on),
 172                      sr2 = debug_atomic_read(&redundant_softirqs_off);
 173
 174         seq_printf(m, " chain lookup misses:           %11u\n",
 175                 debug_atomic_read(&chain_lookup_misses));
 176         seq_printf(m, " chain lookup hits:             %11u\n",
 177                 debug_atomic_read(&chain_lookup_hits));
 178         seq_printf(m, " cyclic checks:                 %11u\n",
 179                 debug_atomic_read(&nr_cyclic_checks));
 180         seq_printf(m, " cyclic-check recursions:       %11u\n",
 181                 debug_atomic_read(&nr_cyclic_check_recursions));
 182         seq_printf(m, " find-mask forwards checks:     %11u\n",
 183                 debug_atomic_read(&nr_find_usage_forwards_checks));
 184         seq_printf(m, " find-mask forwards recursions: %11u\n",
 185                 debug_atomic_read(&nr_find_usage_forwards_recursions));
 186         seq_printf(m, " find-mask backwards checks:    %11u\n",
 187                 debug_atomic_read(&nr_find_usage_backwards_checks));
 188         seq_printf(m, " find-mask backwards recursions:%11u\n",
 189                 debug_atomic_read(&nr_find_usage_backwards_recursions));
 190
 191         seq_printf(m, " hardirq on events:             %11u\n", hi1);
 192         seq_printf(m, " hardirq off events:            %11u\n", hi2);
 193         seq_printf(m, " redundant hardirq ons:         %11u\n", hr1);
 194         seq_printf(m, " redundant hardirq offs:        %11u\n", hr2);
 195         seq_printf(m, " softirq on events:             %11u\n", si1);
 196         seq_printf(m, " softirq off events:            %11u\n", si2);
 197         seq_printf(m, " redundant softirq ons:         %11u\n", sr1);
 198         seq_printf(m, " redundant softirq offs:        %11u\n", sr2);
 199 #endif
 200 }
 201
 202 static int lockdep_stats_show(struct seq_file *m, void *v)
 203 {
 204         struct lock_class *class;
 205         unsigned long nr_unused = 0, nr_uncategorized = 0,
 206                       nr_irq_safe = 0, nr_irq_unsafe = 0,
 207                       nr_softirq_safe = 0, nr_softirq_unsafe = 0,
 208                       nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
 209                       nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
 210                       nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
 211                       nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
 212                       sum_forward_deps = 0, factor = 0;
 213
 214         list_for_each_entry(class, &all_lock_classes, lock_entry) {
 215
 216                 if (class->usage_mask == 0)
 217                         nr_unused++;
 218                 if (class->usage_mask == LOCKF_USED)
 219                         nr_uncategorized++;
 220                 if (class->usage_mask & LOCKF_USED_IN_IRQ)
 221                         nr_irq_safe++;
 222                 if (class->usage_mask & LOCKF_ENABLED_IRQS)
 223                         nr_irq_unsafe++;
 224                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
 225                         nr_softirq_safe++;
 226                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
 227                         nr_softirq_unsafe++;
 228                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
 229                         nr_hardirq_safe++;
 230                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
 231                         nr_hardirq_unsafe++;
 232                 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
 233                         nr_irq_read_safe++;
 234                 if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
 235                         nr_irq_read_unsafe++;
 236                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
 237                         nr_softirq_read_safe++;
 238                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
 239                         nr_softirq_read_unsafe++;
 240                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
 241                         nr_hardirq_read_safe++;
 242                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
 243                         nr_hardirq_read_unsafe++;
 244
 245                 sum_forward_deps += count_forward_deps(class);
 246         }
 247 #ifdef CONFIG_DEBUG_LOCKDEP
 248         DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
 249 #endif
 250         seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
 251                         nr_lock_classes, MAX_LOCKDEP_KEYS);
 252         seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
 253                         nr_list_entries, MAX_LOCKDEP_ENTRIES);
 254         seq_printf(m, " indirect dependencies:         %11lu\n",
 255                         sum_forward_deps);
 256
 257         /*
 258          * Total number of dependencies:
 259          *
 260          * All irq-safe locks may nest inside irq-unsafe locks,
 261          * plus all the other known dependencies:
 262          */
 263         seq_printf(m, " all direct dependencies:       %11lu\n",
 264                         nr_irq_unsafe * nr_irq_safe +
 265                         nr_hardirq_unsafe * nr_hardirq_safe +
 266                         nr_list_entries);
 267
 268         /*
 269          * Estimated factor between direct and indirect
 270          * dependencies:
 271          */
 272         if (nr_list_entries)
 273                 factor = sum_forward_deps / nr_list_entries;
 274
 275         seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
 276                         nr_lock_chains, MAX_LOCKDEP_CHAINS);
 277
 278 #ifdef CONFIG_TRACE_IRQFLAGS
 279         seq_printf(m, " in-hardirq chains:             %11u\n",
 280                         nr_hardirq_chains);
 281         seq_printf(m, " in-softirq chains:             %11u\n",
 282                         nr_softirq_chains);
 283 #endif
 284         seq_printf(m, " in-process chains:             %11u\n",
 285                         nr_process_chains);
 286         seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
 287                         nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
 288         seq_printf(m, " combined max dependencies:     %11u\n",
 289                         (nr_hardirq_chains + 1) *
 290                         (nr_softirq_chains + 1) *
 291                         (nr_process_chains + 1)
 292         );
 293         seq_printf(m, " hardirq-safe locks:            %11lu\n",
 294                         nr_hardirq_safe);
 295         seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
 296                         nr_hardirq_unsafe);
 297         seq_printf(m, " softirq-safe locks:            %11lu\n",
 298                         nr_softirq_safe);
 299         seq_printf(m, " softirq-unsafe locks:          %11lu\n",
 300                         nr_softirq_unsafe);
 301         seq_printf(m, " irq-safe locks:                %11lu\n",
 302                         nr_irq_safe);
 303         seq_printf(m, " irq-unsafe locks:              %11lu\n",
 304                         nr_irq_unsafe);
 305
 306         seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
 307                         nr_hardirq_read_safe);
 308         seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
 309                         nr_hardirq_read_unsafe);
 310         seq_printf(m, " softirq-read-safe locks:       %11lu\n",
 311                         nr_softirq_read_safe);
 312         seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
 313                         nr_softirq_read_unsafe);
 314         seq_printf(m, " irq-read-safe locks:           %11lu\n",
 315                         nr_irq_read_safe);
 316         seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
 317                         nr_irq_read_unsafe);
 318
 319         seq_printf(m, " uncategorized locks:           %11lu\n",
 320                         nr_uncategorized);
 321         seq_printf(m, " unused locks:                  %11lu\n",
 322                         nr_unused);
 323         seq_printf(m, " max locking depth:             %11u\n",
 324                         max_lockdep_depth);
 325         seq_printf(m, " max recursion depth:           %11u\n",
 326                         max_recursion_depth);
 327         lockdep_stats_debug_show(m);
 328         seq_printf(m, " debug_locks:                   %11u\n",
 329                         debug_locks);
 330
 331         return 0;
 332 }
 333
 334 static int lockdep_stats_open(struct inode *inode, struct file *file)
 335 {
 336         return single_open(file, lockdep_stats_show, NULL);
 337 }
 338
 339 static const struct file_operations proc_lockdep_stats_operations = {
 340         .open           = lockdep_stats_open,
 341         .read           = seq_read,
 342         .llseek         = seq_lseek,
 343         .release        = seq_release,
 344 };
 345
 346 static int __init lockdep_proc_init(void)
 347 {
 348         struct proc_dir_entry *entry;
 349
 350         entry = create_proc_entry("lockdep", S_IRUSR, NULL);
 351         if (entry)
 352                 entry->proc_fops = &proc_lockdep_operations;
 353
 354         entry = create_proc_entry("lockdep_stats", S_IRUSR, NULL);
 355         if (entry)
 356                 entry->proc_fops = &proc_lockdep_stats_operations;
 357
 358         return 0;
 359 }
 360
 361 __initcall(lockdep_proc_init);
 362