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Diffstat (limited to 'kernel/locking/lockdep.c')
-rw-r--r--kernel/locking/lockdep.c116
1 files changed, 30 insertions, 86 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index dd13f865ad40..1efada2dd9dd 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -138,7 +138,7 @@ static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
* get freed - this significantly simplifies the debugging code.
*/
unsigned long nr_lock_classes;
-static struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
+struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
static inline struct lock_class *hlock_class(struct held_lock *hlock)
{
@@ -1391,7 +1391,9 @@ static void print_lock_class_header(struct lock_class *class, int depth)
printk("%*s->", depth, "");
print_lock_name(class);
- printk(KERN_CONT " ops: %lu", class->ops);
+#ifdef CONFIG_DEBUG_LOCKDEP
+ printk(KERN_CONT " ops: %lu", debug_class_ops_read(class));
+#endif
printk(KERN_CONT " {\n");
for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
@@ -2148,76 +2150,6 @@ static int check_no_collision(struct task_struct *curr,
}
/*
- * This is for building a chain between just two different classes,
- * instead of adding a new hlock upon current, which is done by
- * add_chain_cache().
- *
- * This can be called in any context with two classes, while
- * add_chain_cache() must be done within the lock owener's context
- * since it uses hlock which might be racy in another context.
- */
-static inline int add_chain_cache_classes(unsigned int prev,
- unsigned int next,
- unsigned int irq_context,
- u64 chain_key)
-{
- struct hlist_head *hash_head = chainhashentry(chain_key);
- struct lock_chain *chain;
-
- /*
- * Allocate a new chain entry from the static array, and add
- * it to the hash:
- */
-
- /*
- * We might need to take the graph lock, ensure we've got IRQs
- * disabled to make this an IRQ-safe lock.. for recursion reasons
- * lockdep won't complain about its own locking errors.
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return 0;
-
- if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!");
- dump_stack();
- return 0;
- }
-
- chain = lock_chains + nr_lock_chains++;
- chain->chain_key = chain_key;
- chain->irq_context = irq_context;
- chain->depth = 2;
- if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
- chain->base = nr_chain_hlocks;
- nr_chain_hlocks += chain->depth;
- chain_hlocks[chain->base] = prev - 1;
- chain_hlocks[chain->base + 1] = next -1;
- }
-#ifdef CONFIG_DEBUG_LOCKDEP
- /*
- * Important for check_no_collision().
- */
- else {
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!");
- dump_stack();
- return 0;
- }
-#endif
-
- hlist_add_head_rcu(&chain->entry, hash_head);
- debug_atomic_inc(chain_lookup_misses);
- inc_chains();
-
- return 1;
-}
-
-/*
* Adds a dependency chain into chain hashtable. And must be called with
* graph_lock held.
*
@@ -3262,6 +3194,10 @@ static int __lock_is_held(const struct lockdep_map *lock, int read);
/*
* This gets called for every mutex_lock*()/spin_lock*() operation.
* We maintain the dependency maps and validate the locking attempt:
+ *
+ * The callers must make sure that IRQs are disabled before calling it,
+ * otherwise we could get an interrupt which would want to take locks,
+ * which would end up in lockdep again.
*/
static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
int trylock, int read, int check, int hardirqs_off,
@@ -3279,14 +3215,6 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
if (unlikely(!debug_locks))
return 0;
- /*
- * Lockdep should run with IRQs disabled, otherwise we could
- * get an interrupt which would want to take locks, which would
- * end up in lockdep and have you got a head-ache already?
- */
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return 0;
-
if (!prove_locking || lock->key == &__lockdep_no_validate__)
check = 0;
@@ -3300,7 +3228,9 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
if (!class)
return 0;
}
- atomic_inc((atomic_t *)&class->ops);
+
+ debug_class_ops_inc(class);
+
if (very_verbose(class)) {
printk("\nacquire class [%px] %s", class->key, class->name);
if (class->name_version > 1)
@@ -3543,6 +3473,9 @@ static int reacquire_held_locks(struct task_struct *curr, unsigned int depth,
{
struct held_lock *hlock;
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return 0;
+
for (hlock = curr->held_locks + idx; idx < depth; idx++, hlock++) {
if (!__lock_acquire(hlock->instance,
hlock_class(hlock)->subclass,
@@ -3696,6 +3629,13 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
curr->lockdep_depth = i;
curr->curr_chain_key = hlock->prev_chain_key;
+ /*
+ * The most likely case is when the unlock is on the innermost
+ * lock. In this case, we are done!
+ */
+ if (i == depth-1)
+ return 1;
+
if (reacquire_held_locks(curr, depth, i + 1))
return 0;
@@ -3703,10 +3643,14 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
* We had N bottles of beer on the wall, we drank one, but now
* there's not N-1 bottles of beer left on the wall...
*/
- if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
- return 0;
+ DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth-1);
- return 1;
+ /*
+ * Since reacquire_held_locks() would have called check_chain_key()
+ * indirectly via __lock_acquire(), we don't need to do it again
+ * on return.
+ */
+ return 0;
}
static int __lock_is_held(const struct lockdep_map *lock, int read)
@@ -4122,7 +4066,7 @@ void lock_contended(struct lockdep_map *lock, unsigned long ip)
{
unsigned long flags;
- if (unlikely(!lock_stat))
+ if (unlikely(!lock_stat || !debug_locks))
return;
if (unlikely(current->lockdep_recursion))
@@ -4142,7 +4086,7 @@ void lock_acquired(struct lockdep_map *lock, unsigned long ip)
{
unsigned long flags;
- if (unlikely(!lock_stat))
+ if (unlikely(!lock_stat || !debug_locks))
return;
if (unlikely(current->lockdep_recursion))