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/module.h>
  14 #include <linux/proc_fs.h>
  15 #include <linux/seq_file.h>
  16 #include <linux/kallsyms.h>
  17 #include <linux/debug_locks.h>
  18
  19 #include "lockdep_internals.h"
  20
  21 static void *l_next(struct seq_file *m, void *v, loff_t *pos)
  22 {
  23         struct lock_class *class = v;
  24
  25         (*pos)++;
  26
  27         if (class->lock_entry.next != &all_lock_classes)
  28                 class = list_entry(class->lock_entry.next, struct lock_class,
  29                                   lock_entry);
  30         else
  31                 class = NULL;
  32         m->private = class;
  33
  34         return class;
  35 }
  36
  37 static void *l_start(struct seq_file *m, loff_t *pos)
  38 {
  39         struct lock_class *class = m->private;
  40
  41         if (&class->lock_entry == all_lock_classes.next)
  42                 seq_printf(m, "all lock classes:\n");
  43
  44         return class;
  45 }
  46
  47 static void l_stop(struct seq_file *m, void *v)
  48 {
  49 }
  50
  51 static unsigned long count_forward_deps(struct lock_class *class)
  52 {
  53         struct lock_list *entry;
  54         unsigned long ret = 1;
  55
  56         /*
  57          * Recurse this class's dependency list:
  58          */
  59         list_for_each_entry(entry, &class->locks_after, entry)
  60                 ret += count_forward_deps(entry->class);
  61
  62         return ret;
  63 }
  64
  65 static unsigned long count_backward_deps(struct lock_class *class)
  66 {
  67         struct lock_list *entry;
  68         unsigned long ret = 1;
  69
  70         /*
  71          * Recurse this class's dependency list:
  72          */
  73         list_for_each_entry(entry, &class->locks_before, entry)
  74                 ret += count_backward_deps(entry->class);
  75
  76         return ret;
  77 }
  78
  79 static void print_name(struct seq_file *m, struct lock_class *class)
  80 {
  81         char str[128];
  82         const char *name = class->name;
  83
  84         if (!name) {
  85                 name = __get_key_name(class->key, str);
  86                 seq_printf(m, "%s", name);
  87         } else{
  88                 seq_printf(m, "%s", name);
  89                 if (class->name_version > 1)
  90                         seq_printf(m, "#%d", class->name_version);
  91                 if (class->subclass)
  92                         seq_printf(m, "/%d", class->subclass);
  93         }
  94 }
  95
  96 static int l_show(struct seq_file *m, void *v)
  97 {
  98         unsigned long nr_forward_deps, nr_backward_deps;
  99         struct lock_class *class = m->private;
 100         struct lock_list *entry;
 101         char c1, c2, c3, c4;
 102
 103         seq_printf(m, "%p", class->key);
 104 #ifdef CONFIG_DEBUG_LOCKDEP
 105         seq_printf(m, " OPS:%8ld", class->ops);
 106 #endif
 107         nr_forward_deps = count_forward_deps(class);
 108         seq_printf(m, " FD:%5ld", nr_forward_deps);
 109
 110         nr_backward_deps = count_backward_deps(class);
 111         seq_printf(m, " BD:%5ld", nr_backward_deps);
 112
 113         get_usage_chars(class, &c1, &c2, &c3, &c4);
 114         seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
 115
 116         seq_printf(m, ": ");
 117         print_name(m, class);
 118         seq_puts(m, "\n");
 119
 120         list_for_each_entry(entry, &class->locks_after, entry) {
 121                 if (entry->distance == 1) {
 122                         seq_printf(m, " -> [%p] ", entry->class);
 123                         print_name(m, entry->class);
 124                         seq_puts(m, "\n");
 125                 }
 126         }
 127         seq_puts(m, "\n");
 128
 129         return 0;
 130 }
 131
 132 static const struct seq_operations lockdep_ops = {
 133         .start  = l_start,
 134         .next   = l_next,
 135         .stop   = l_stop,
 136         .show   = l_show,
 137 };
 138
 139 static int lockdep_open(struct inode *inode, struct file *file)
 140 {
 141         int res = seq_open(file, &lockdep_ops);
 142         if (!res) {
 143                 struct seq_file *m = file->private_data;
 144
 145                 if (!list_empty(&all_lock_classes))
 146                         m->private = list_entry(all_lock_classes.next,
 147                                         struct lock_class, lock_entry);
 148                 else
 149                         m->private = NULL;
 150         }
 151         return res;
 152 }
 153
 154 static const struct file_operations proc_lockdep_operations = {
 155         .open           = lockdep_open,
 156         .read           = seq_read,
 157         .llseek         = seq_lseek,
 158         .release        = seq_release,
 159 };
 160
 161 static void lockdep_stats_debug_show(struct seq_file *m)
 162 {
 163 #ifdef CONFIG_DEBUG_LOCKDEP
 164         unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
 165                      hi2 = debug_atomic_read(&hardirqs_off_events),
 166                      hr1 = debug_atomic_read(&redundant_hardirqs_on),
 167                      hr2 = debug_atomic_read(&redundant_hardirqs_off),
 168                      si1 = debug_atomic_read(&softirqs_on_events),
 169                      si2 = debug_atomic_read(&softirqs_off_events),
 170                      sr1 = debug_atomic_read(&redundant_softirqs_on),
 171                      sr2 = debug_atomic_read(&redundant_softirqs_off);
 172
 173         seq_printf(m, " chain lookup misses:           %11u\n",
 174                 debug_atomic_read(&chain_lookup_misses));
 175         seq_printf(m, " chain lookup hits:             %11u\n",
 176                 debug_atomic_read(&chain_lookup_hits));
 177         seq_printf(m, " cyclic checks:                 %11u\n",
 178                 debug_atomic_read(&nr_cyclic_checks));
 179         seq_printf(m, " cyclic-check recursions:       %11u\n",
 180                 debug_atomic_read(&nr_cyclic_check_recursions));
 181         seq_printf(m, " find-mask forwards checks:     %11u\n",
 182                 debug_atomic_read(&nr_find_usage_forwards_checks));
 183         seq_printf(m, " find-mask forwards recursions: %11u\n",
 184                 debug_atomic_read(&nr_find_usage_forwards_recursions));
 185         seq_printf(m, " find-mask backwards checks:    %11u\n",
 186                 debug_atomic_read(&nr_find_usage_backwards_checks));
 187         seq_printf(m, " find-mask backwards recursions:%11u\n",
 188                 debug_atomic_read(&nr_find_usage_backwards_recursions));
 189
 190         seq_printf(m, " hardirq on events:             %11u\n", hi1);
 191         seq_printf(m, " hardirq off events:            %11u\n", hi2);
 192         seq_printf(m, " redundant hardirq ons:         %11u\n", hr1);
 193         seq_printf(m, " redundant hardirq offs:        %11u\n", hr2);
 194         seq_printf(m, " softirq on events:             %11u\n", si1);
 195         seq_printf(m, " softirq off events:            %11u\n", si2);
 196         seq_printf(m, " redundant softirq ons:         %11u\n", sr1);
 197         seq_printf(m, " redundant softirq offs:        %11u\n", sr2);
 198 #endif
 199 }
 200
 201 static int lockdep_stats_show(struct seq_file *m, void *v)
 202 {
 203         struct lock_class *class;
 204         unsigned long nr_unused = 0, nr_uncategorized = 0,
 205                       nr_irq_safe = 0, nr_irq_unsafe = 0,
 206                       nr_softirq_safe = 0, nr_softirq_unsafe = 0,
 207                       nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
 208                       nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
 209                       nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
 210                       nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
 211                       sum_forward_deps = 0, factor = 0;
 212
 213         list_for_each_entry(class, &all_lock_classes, lock_entry) {
 214
 215                 if (class->usage_mask == 0)
 216                         nr_unused++;
 217                 if (class->usage_mask == LOCKF_USED)
 218                         nr_uncategorized++;
 219                 if (class->usage_mask & LOCKF_USED_IN_IRQ)
 220                         nr_irq_safe++;
 221                 if (class->usage_mask & LOCKF_ENABLED_IRQS)
 222                         nr_irq_unsafe++;
 223                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
 224                         nr_softirq_safe++;
 225                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
 226                         nr_softirq_unsafe++;
 227                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
 228                         nr_hardirq_safe++;
 229                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
 230                         nr_hardirq_unsafe++;
 231                 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
 232                         nr_irq_read_safe++;
 233                 if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
 234                         nr_irq_read_unsafe++;
 235                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
 236                         nr_softirq_read_safe++;
 237                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
 238                         nr_softirq_read_unsafe++;
 239                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
 240                         nr_hardirq_read_safe++;
 241                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
 242                         nr_hardirq_read_unsafe++;
 243
 244                 sum_forward_deps += count_forward_deps(class);
 245         }
 246 #ifdef CONFIG_DEBUG_LOCKDEP
 247         DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
 248 #endif
 249         seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
 250                         nr_lock_classes, MAX_LOCKDEP_KEYS);
 251         seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
 252                         nr_list_entries, MAX_LOCKDEP_ENTRIES);
 253         seq_printf(m, " indirect dependencies:         %11lu\n",
 254                         sum_forward_deps);
 255
 256         /*
 257          * Total number of dependencies:
 258          *
 259          * All irq-safe locks may nest inside irq-unsafe locks,
 260          * plus all the other known dependencies:
 261          */
 262         seq_printf(m, " all direct dependencies:       %11lu\n",
 263                         nr_irq_unsafe * nr_irq_safe +
 264                         nr_hardirq_unsafe * nr_hardirq_safe +
 265                         nr_list_entries);
 266
 267         /*
 268          * Estimated factor between direct and indirect
 269          * dependencies:
 270          */
 271         if (nr_list_entries)
 272                 factor = sum_forward_deps / nr_list_entries;
 273
 274         seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
 275                         nr_lock_chains, MAX_LOCKDEP_CHAINS);
 276
 277 #ifdef CONFIG_TRACE_IRQFLAGS
 278         seq_printf(m, " in-hardirq chains:             %11u\n",
 279                         nr_hardirq_chains);
 280         seq_printf(m, " in-softirq chains:             %11u\n",
 281                         nr_softirq_chains);
 282 #endif
 283         seq_printf(m, " in-process chains:             %11u\n",
 284                         nr_process_chains);
 285         seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
 286                         nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
 287         seq_printf(m, " combined max dependencies:     %11u\n",
 288                         (nr_hardirq_chains + 1) *
 289                         (nr_softirq_chains + 1) *
 290                         (nr_process_chains + 1)
 291         );
 292         seq_printf(m, " hardirq-safe locks:            %11lu\n",
 293                         nr_hardirq_safe);
 294         seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
 295                         nr_hardirq_unsafe);
 296         seq_printf(m, " softirq-safe locks:            %11lu\n",
 297                         nr_softirq_safe);
 298         seq_printf(m, " softirq-unsafe locks:          %11lu\n",
 299                         nr_softirq_unsafe);
 300         seq_printf(m, " irq-safe locks:                %11lu\n",
 301                         nr_irq_safe);
 302         seq_printf(m, " irq-unsafe locks:              %11lu\n",
 303                         nr_irq_unsafe);
 304
 305         seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
 306                         nr_hardirq_read_safe);
 307         seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
 308                         nr_hardirq_read_unsafe);
 309         seq_printf(m, " softirq-read-safe locks:       %11lu\n",
 310                         nr_softirq_read_safe);
 311         seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
 312                         nr_softirq_read_unsafe);
 313         seq_printf(m, " irq-read-safe locks:           %11lu\n",
 314                         nr_irq_read_safe);
 315         seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
 316                         nr_irq_read_unsafe);
 317
 318         seq_printf(m, " uncategorized locks:           %11lu\n",
 319                         nr_uncategorized);
 320         seq_printf(m, " unused locks:                  %11lu\n",
 321                         nr_unused);
 322         seq_printf(m, " max locking depth:             %11u\n",
 323                         max_lockdep_depth);
 324         seq_printf(m, " max recursion depth:           %11u\n",
 325                         max_recursion_depth);
 326         lockdep_stats_debug_show(m);
 327         seq_printf(m, " debug_locks:                   %11u\n",
 328                         debug_locks);
 329
 330         return 0;
 331 }
 332
 333 static int lockdep_stats_open(struct inode *inode, struct file *file)
 334 {
 335         return single_open(file, lockdep_stats_show, NULL);
 336 }
 337
 338 static const struct file_operations proc_lockdep_stats_operations = {
 339         .open           = lockdep_stats_open,
 340         .read           = seq_read,
 341         .llseek         = seq_lseek,
 342         .release        = single_release,
 343 };
 344
 345 static int __init lockdep_proc_init(void)
 346 {
 347         struct proc_dir_entry *entry;
 348
 349         entry = create_proc_entry("lockdep", S_IRUSR, NULL);
 350         if (entry)
 351                 entry->proc_fops = &proc_lockdep_operations;
 352
 353         entry = create_proc_entry("lockdep_stats", S_IRUSR, NULL);
 354         if (entry)
 355                 entry->proc_fops = &proc_lockdep_stats_operations;
 356
 357         return 0;
 358 }
 359
 360 __initcall(lockdep_proc_init);
 361