lib/spinlock_debug.c

   1 /*
   2  * Copyright 2005, Red Hat, Inc., Ingo Molnar
   3  * Released under the General Public License (GPL).
   4  *
   5  * This file contains the spinlock/rwlock implementations for
   6  * DEBUG_SPINLOCK.
   7  */
   8
   9 #include <linux/config.h>
  10 #include <linux/spinlock.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/delay.h>
  13
  14 static void spin_bug(spinlock_t *lock, const char *msg)
  15 {
  16         static long print_once = 1;
  17         struct task_struct *owner = NULL;
  18
  19         if (xchg(&print_once, 0)) {
  20                 if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
  21                         owner = lock->owner;
  22                 printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
  23                         msg, raw_smp_processor_id(),
  24                         current->comm, current->pid);
  25                 printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, "
  26                                 ".owner_cpu: %d\n",
  27                         lock, lock->magic,
  28                         owner ? owner->comm : "<none>",
  29                         owner ? owner->pid : -1,
  30                         lock->owner_cpu);
  31                 dump_stack();
  32 #ifdef CONFIG_SMP
  33                 /*
  34                  * We cannot continue on SMP:
  35                  */
  36 //              panic("bad locking");
  37 #endif
  38         }
  39 }
  40
  41 #define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
  42
  43 static inline void debug_spin_lock_before(spinlock_t *lock)
  44 {
  45         SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
  46         SPIN_BUG_ON(lock->owner == current, lock, "recursion");
  47         SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
  48                                                         lock, "cpu recursion");
  49 }
  50
  51 static inline void debug_spin_lock_after(spinlock_t *lock)
  52 {
  53         lock->owner_cpu = raw_smp_processor_id();
  54         lock->owner = current;
  55 }
  56
  57 static inline void debug_spin_unlock(spinlock_t *lock)
  58 {
  59         SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
  60         SPIN_BUG_ON(!spin_is_locked(lock), lock, "already unlocked");
  61         SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
  62         SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
  63                                                         lock, "wrong CPU");
  64         lock->owner = SPINLOCK_OWNER_INIT;
  65         lock->owner_cpu = -1;
  66 }
  67
  68 static void __spin_lock_debug(spinlock_t *lock)
  69 {
  70         int print_once = 1;
  71         u64 i;
  72
  73         for (;;) {
  74                 for (i = 0; i < loops_per_jiffy * HZ; i++) {
  75                         cpu_relax();
  76                         if (__raw_spin_trylock(&lock->raw_lock))
  77                                 return;
  78                 }
  79                 /* lockup suspected: */
  80                 if (print_once) {
  81                         print_once = 0;
  82                         printk(KERN_EMERG "BUG: spinlock lockup on CPU#%d, "
  83                                         "%s/%d, %p\n",
  84                                 raw_smp_processor_id(), current->comm,
  85                                 current->pid, lock);
  86                         dump_stack();
  87                 }
  88         }
  89 }
  90
  91 void _raw_spin_lock(spinlock_t *lock)
  92 {
  93         debug_spin_lock_before(lock);
  94         if (unlikely(!__raw_spin_trylock(&lock->raw_lock)))
  95                 __spin_lock_debug(lock);
  96         debug_spin_lock_after(lock);
  97 }
  98
  99 int _raw_spin_trylock(spinlock_t *lock)
 100 {
 101         int ret = __raw_spin_trylock(&lock->raw_lock);
 102
 103         if (ret)
 104                 debug_spin_lock_after(lock);
 105 #ifndef CONFIG_SMP
 106         /*
 107          * Must not happen on UP:
 108          */
 109         SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
 110 #endif
 111         return ret;
 112 }
 113
 114 void _raw_spin_unlock(spinlock_t *lock)
 115 {
 116         debug_spin_unlock(lock);
 117         __raw_spin_unlock(&lock->raw_lock);
 118 }
 119
 120 static void rwlock_bug(rwlock_t *lock, const char *msg)
 121 {
 122         static long print_once = 1;
 123
 124         if (xchg(&print_once, 0)) {
 125                 printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
 126                         msg, raw_smp_processor_id(), current->comm,
 127                         current->pid, lock);
 128                 dump_stack();
 129 #ifdef CONFIG_SMP
 130                 /*
 131                  * We cannot continue on SMP:
 132                  */
 133                 panic("bad locking");
 134 #endif
 135         }
 136 }
 137
 138 #define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
 139
 140 static void __read_lock_debug(rwlock_t *lock)
 141 {
 142         int print_once = 1;
 143         u64 i;
 144
 145         for (;;) {
 146                 for (i = 0; i < loops_per_jiffy * HZ; i++) {
 147                         cpu_relax();
 148                         if (__raw_read_trylock(&lock->raw_lock))
 149                                 return;
 150                 }
 151                 /* lockup suspected: */
 152                 if (print_once) {
 153                         print_once = 0;
 154                         printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "
 155                                         "%s/%d, %p\n",
 156                                 raw_smp_processor_id(), current->comm,
 157                                 current->pid, lock);
 158                         dump_stack();
 159                 }
 160         }
 161 }
 162
 163 void _raw_read_lock(rwlock_t *lock)
 164 {
 165         RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
 166         if (unlikely(!__raw_read_trylock(&lock->raw_lock)))
 167                 __read_lock_debug(lock);
 168 }
 169
 170 int _raw_read_trylock(rwlock_t *lock)
 171 {
 172         int ret = __raw_read_trylock(&lock->raw_lock);
 173
 174 #ifndef CONFIG_SMP
 175         /*
 176          * Must not happen on UP:
 177          */
 178         RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
 179 #endif
 180         return ret;
 181 }
 182
 183 void _raw_read_unlock(rwlock_t *lock)
 184 {
 185         RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
 186         __raw_read_unlock(&lock->raw_lock);
 187 }
 188
 189 static inline void debug_write_lock_before(rwlock_t *lock)
 190 {
 191         RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
 192         RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
 193         RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
 194                                                         lock, "cpu recursion");
 195 }
 196
 197 static inline void debug_write_lock_after(rwlock_t *lock)
 198 {
 199         lock->owner_cpu = raw_smp_processor_id();
 200         lock->owner = current;
 201 }
 202
 203 static inline void debug_write_unlock(rwlock_t *lock)
 204 {
 205         RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
 206         RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
 207         RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
 208                                                         lock, "wrong CPU");
 209         lock->owner = SPINLOCK_OWNER_INIT;
 210         lock->owner_cpu = -1;
 211 }
 212
 213 static void __write_lock_debug(rwlock_t *lock)
 214 {
 215         int print_once = 1;
 216         u64 i;
 217
 218         for (;;) {
 219                 for (i = 0; i < loops_per_jiffy * HZ; i++) {
 220                         cpu_relax();
 221                         if (__raw_write_trylock(&lock->raw_lock))
 222                                 return;
 223                 }
 224                 /* lockup suspected: */
 225                 if (print_once) {
 226                         print_once = 0;
 227                         printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "
 228                                         "%s/%d, %p\n",
 229                                 raw_smp_processor_id(), current->comm,
 230                                 current->pid, lock);
 231                         dump_stack();
 232                 }
 233         }
 234 }
 235
 236 void _raw_write_lock(rwlock_t *lock)
 237 {
 238         debug_write_lock_before(lock);
 239         if (unlikely(!__raw_write_trylock(&lock->raw_lock)))
 240                 __write_lock_debug(lock);
 241         debug_write_lock_after(lock);
 242 }
 243
 244 int _raw_write_trylock(rwlock_t *lock)
 245 {
 246         int ret = __raw_write_trylock(&lock->raw_lock);
 247
 248         if (ret)
 249                 debug_write_lock_after(lock);
 250 #ifndef CONFIG_SMP
 251         /*
 252          * Must not happen on UP:
 253          */
 254         RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
 255 #endif
 256         return ret;
 257 }
 258
 259 void _raw_write_unlock(rwlock_t *lock)
 260 {
 261         debug_write_unlock(lock);
 262         __raw_write_unlock(&lock->raw_lock);
 263 }