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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2007-07-19 01:48:54 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-19 10:04:49 -0700
commit8e18257d29238311e82085152741f0c3aa18b74d (patch)
tree4c3e43b3b001763b4280a4b6d754387a52fb4d73
parentca58abcb4a6d52ee2db1b1130cea3ca2a76677b9 (diff)
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lockdep: reduce the ifdeffery
Move code around to get fewer but larger #ifdef sections. Break some in-function #ifdefs out into their own functions. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/lockdep.c1171
-rw-r--r--kernel/lockdep_proc.c2
2 files changed, 630 insertions, 543 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 05c1261791f..87ac3642507 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -95,25 +95,6 @@ static int lockdep_initialized;
unsigned long nr_list_entries;
static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
-#ifdef CONFIG_PROVE_LOCKING
-/*
- * Allocate a lockdep entry. (assumes the graph_lock held, returns
- * with NULL on failure)
- */
-static struct lock_list *alloc_list_entry(void)
-{
- if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
- if (!debug_locks_off_graph_unlock())
- return NULL;
-
- printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
- printk("turning off the locking correctness validator.\n");
- return NULL;
- }
- return list_entries + nr_list_entries++;
-}
-#endif
-
/*
* All data structures here are protected by the global debug_lock.
*
@@ -141,11 +122,6 @@ LIST_HEAD(all_lock_classes);
static struct list_head classhash_table[CLASSHASH_SIZE];
-unsigned long nr_lock_chains;
-#ifdef CONFIG_PROVE_LOCKING
-static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
-#endif
-
/*
* We put the lock dependency chains into a hash-table as well, to cache
* their existence:
@@ -227,26 +203,6 @@ static int verbose(struct lock_class *class)
return 0;
}
-#ifdef CONFIG_TRACE_IRQFLAGS
-
-static int hardirq_verbose(struct lock_class *class)
-{
-#if HARDIRQ_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-static int softirq_verbose(struct lock_class *class)
-{
-#if SOFTIRQ_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-#endif
-
/*
* Stack-trace: tightly packed array of stack backtrace
* addresses. Protected by the graph_lock.
@@ -486,8 +442,258 @@ static void print_lock_dependencies(struct lock_class *class, int depth)
}
}
+static void print_kernel_version(void)
+{
+ printk("%s %.*s\n", init_utsname()->release,
+ (int)strcspn(init_utsname()->version, " "),
+ init_utsname()->version);
+}
+
+static int very_verbose(struct lock_class *class)
+{
+#if VERY_VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
+}
+
+/*
+ * Is this the address of a static object:
+ */
+static int static_obj(void *obj)
+{
+ unsigned long start = (unsigned long) &_stext,
+ end = (unsigned long) &_end,
+ addr = (unsigned long) obj;
+#ifdef CONFIG_SMP
+ int i;
+#endif
+
+ /*
+ * static variable?
+ */
+ if ((addr >= start) && (addr < end))
+ return 1;
+
+#ifdef CONFIG_SMP
+ /*
+ * percpu var?
+ */
+ for_each_possible_cpu(i) {
+ start = (unsigned long) &__per_cpu_start + per_cpu_offset(i);
+ end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM
+ + per_cpu_offset(i);
+
+ if ((addr >= start) && (addr < end))
+ return 1;
+ }
+#endif
+
+ /*
+ * module var?
+ */
+ return is_module_address(addr);
+}
+
+/*
+ * To make lock name printouts unique, we calculate a unique
+ * class->name_version generation counter:
+ */
+static int count_matching_names(struct lock_class *new_class)
+{
+ struct lock_class *class;
+ int count = 0;
+
+ if (!new_class->name)
+ return 0;
+
+ list_for_each_entry(class, &all_lock_classes, lock_entry) {
+ if (new_class->key - new_class->subclass == class->key)
+ return class->name_version;
+ if (class->name && !strcmp(class->name, new_class->name))
+ count = max(count, class->name_version);
+ }
+
+ return count + 1;
+}
+
+/*
+ * Register a lock's class in the hash-table, if the class is not present
+ * yet. Otherwise we look it up. We cache the result in the lock object
+ * itself, so actual lookup of the hash should be once per lock object.
+ */
+static inline struct lock_class *
+look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
+{
+ struct lockdep_subclass_key *key;
+ struct list_head *hash_head;
+ struct lock_class *class;
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+ /*
+ * If the architecture calls into lockdep before initializing
+ * the hashes then we'll warn about it later. (we cannot printk
+ * right now)
+ */
+ if (unlikely(!lockdep_initialized)) {
+ lockdep_init();
+ lockdep_init_error = 1;
+ }
+#endif
+
+ /*
+ * Static locks do not have their class-keys yet - for them the key
+ * is the lock object itself:
+ */
+ if (unlikely(!lock->key))
+ lock->key = (void *)lock;
+
+ /*
+ * NOTE: the class-key must be unique. For dynamic locks, a static
+ * lock_class_key variable is passed in through the mutex_init()
+ * (or spin_lock_init()) call - which acts as the key. For static
+ * locks we use the lock object itself as the key.
+ */
+ BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(struct lock_class));
+
+ key = lock->key->subkeys + subclass;
+
+ hash_head = classhashentry(key);
+
+ /*
+ * We can walk the hash lockfree, because the hash only
+ * grows, and we are careful when adding entries to the end:
+ */
+ list_for_each_entry(class, hash_head, hash_entry)
+ if (class->key == key)
+ return class;
+
+ return NULL;
+}
+
+/*
+ * Register a lock's class in the hash-table, if the class is not present
+ * yet. Otherwise we look it up. We cache the result in the lock object
+ * itself, so actual lookup of the hash should be once per lock object.
+ */
+static inline struct lock_class *
+register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
+{
+ struct lockdep_subclass_key *key;
+ struct list_head *hash_head;
+ struct lock_class *class;
+ unsigned long flags;
+
+ class = look_up_lock_class(lock, subclass);
+ if (likely(class))
+ return class;
+
+ /*
+ * Debug-check: all keys must be persistent!
+ */
+ if (!static_obj(lock->key)) {
+ debug_locks_off();
+ printk("INFO: trying to register non-static key.\n");
+ printk("the code is fine but needs lockdep annotation.\n");
+ printk("turning off the locking correctness validator.\n");
+ dump_stack();
+
+ return NULL;
+ }
+
+ key = lock->key->subkeys + subclass;
+ hash_head = classhashentry(key);
+
+ raw_local_irq_save(flags);
+ if (!graph_lock()) {
+ raw_local_irq_restore(flags);
+ return NULL;
+ }
+ /*
+ * We have to do the hash-walk again, to avoid races
+ * with another CPU:
+ */
+ list_for_each_entry(class, hash_head, hash_entry)
+ if (class->key == key)
+ goto out_unlock_set;
+ /*
+ * Allocate a new key from the static array, and add it to
+ * the hash:
+ */
+ if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
+ if (!debug_locks_off_graph_unlock()) {
+ raw_local_irq_restore(flags);
+ return NULL;
+ }
+ raw_local_irq_restore(flags);
+
+ printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
+ printk("turning off the locking correctness validator.\n");
+ return NULL;
+ }
+ class = lock_classes + nr_lock_classes++;
+ debug_atomic_inc(&nr_unused_locks);
+ class->key = key;
+ class->name = lock->name;
+ class->subclass = subclass;
+ INIT_LIST_HEAD(&class->lock_entry);
+ INIT_LIST_HEAD(&class->locks_before);
+ INIT_LIST_HEAD(&class->locks_after);
+ class->name_version = count_matching_names(class);
+ /*
+ * We use RCU's safe list-add method to make
+ * parallel walking of the hash-list safe:
+ */
+ list_add_tail_rcu(&class->hash_entry, hash_head);
+
+ if (verbose(class)) {
+ graph_unlock();
+ raw_local_irq_restore(flags);
+
+ printk("\nnew class %p: %s", class->key, class->name);
+ if (class->name_version > 1)
+ printk("#%d", class->name_version);
+ printk("\n");
+ dump_stack();
+
+ raw_local_irq_save(flags);
+ if (!graph_lock()) {
+ raw_local_irq_restore(flags);
+ return NULL;
+ }
+ }
+out_unlock_set:
+ graph_unlock();
+ raw_local_irq_restore(flags);
+
+ if (!subclass || force)
+ lock->class_cache = class;
+
+ if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
+ return NULL;
+
+ return class;
+}
+
#ifdef CONFIG_PROVE_LOCKING
/*
+ * Allocate a lockdep entry. (assumes the graph_lock held, returns
+ * with NULL on failure)
+ */
+static struct lock_list *alloc_list_entry(void)
+{
+ if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
+ if (!debug_locks_off_graph_unlock())
+ return NULL;
+
+ printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
+ printk("turning off the locking correctness validator.\n");
+ return NULL;
+ }
+ return list_entries + nr_list_entries++;
+}
+
+/*
* Add a new dependency to the head of the list:
*/
static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
@@ -546,16 +752,7 @@ print_circular_bug_entry(struct lock_list *target, unsigned int depth)
return 0;
}
-#endif
-static void print_kernel_version(void)
-{
- printk("%s %.*s\n", init_utsname()->release,
- (int)strcspn(init_utsname()->version, " "),
- init_utsname()->version);
-}
-
-#ifdef CONFIG_PROVE_LOCKING
/*
* When a circular dependency is detected, print the
* header first:
@@ -646,17 +843,8 @@ check_noncircular(struct lock_class *source, unsigned int depth)
}
return 1;
}
-#endif
-static int very_verbose(struct lock_class *class)
-{
-#if VERY_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
#ifdef CONFIG_TRACE_IRQFLAGS
-
/*
* Forwards and backwards subgraph searching, for the purposes of
* proving that two subgraphs can be connected by a new dependency
@@ -829,9 +1017,80 @@ check_usage(struct task_struct *curr, struct held_lock *prev,
bit_backwards, bit_forwards, irqclass);
}
+static int
+check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next)
+{
+ /*
+ * Prove that the new dependency does not connect a hardirq-safe
+ * lock with a hardirq-unsafe lock - to achieve this we search
+ * the backwards-subgraph starting at <prev>, and the
+ * forwards-subgraph starting at <next>:
+ */
+ if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ,
+ LOCK_ENABLED_HARDIRQS, "hard"))
+ return 0;
+
+ /*
+ * Prove that the new dependency does not connect a hardirq-safe-read
+ * lock with a hardirq-unsafe lock - to achieve this we search
+ * the backwards-subgraph starting at <prev>, and the
+ * forwards-subgraph starting at <next>:
+ */
+ if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ,
+ LOCK_ENABLED_HARDIRQS, "hard-read"))
+ return 0;
+
+ /*
+ * Prove that the new dependency does not connect a softirq-safe
+ * lock with a softirq-unsafe lock - to achieve this we search
+ * the backwards-subgraph starting at <prev>, and the
+ * forwards-subgraph starting at <next>:
+ */
+ if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ,
+ LOCK_ENABLED_SOFTIRQS, "soft"))
+ return 0;
+ /*
+ * Prove that the new dependency does not connect a softirq-safe-read
+ * lock with a softirq-unsafe lock - to achieve this we search
+ * the backwards-subgraph starting at <prev>, and the
+ * forwards-subgraph starting at <next>:
+ */
+ if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ,
+ LOCK_ENABLED_SOFTIRQS, "soft"))
+ return 0;
+
+ return 1;
+}
+
+static void inc_chains(void)
+{
+ if (current->hardirq_context)
+ nr_hardirq_chains++;
+ else {
+ if (current->softirq_context)
+ nr_softirq_chains++;
+ else
+ nr_process_chains++;
+ }
+}
+
+#else
+
+static inline int
+check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next)
+{
+ return 1;
+}
+
+static inline void inc_chains(void)
+{
+ nr_process_chains++;
+}
+
#endif
-#ifdef CONFIG_PROVE_LOCKING
static int
print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
struct held_lock *next)
@@ -931,47 +1190,10 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
if (!(check_noncircular(next->class, 0)))
return print_circular_bug_tail();
-#ifdef CONFIG_TRACE_IRQFLAGS
- /*
- * Prove that the new dependency does not connect a hardirq-safe
- * lock with a hardirq-unsafe lock - to achieve this we search
- * the backwards-subgraph starting at <prev>, and the
- * forwards-subgraph starting at <next>:
- */
- if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ,
- LOCK_ENABLED_HARDIRQS, "hard"))
- return 0;
-
- /*
- * Prove that the new dependency does not connect a hardirq-safe-read
- * lock with a hardirq-unsafe lock - to achieve this we search
- * the backwards-subgraph starting at <prev>, and the
- * forwards-subgraph starting at <next>:
- */
- if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ,
- LOCK_ENABLED_HARDIRQS, "hard-read"))
+ if (!check_prev_add_irq(curr, prev, next))
return 0;
/*
- * Prove that the new dependency does not connect a softirq-safe
- * lock with a softirq-unsafe lock - to achieve this we search
- * the backwards-subgraph starting at <prev>, and the
- * forwards-subgraph starting at <next>:
- */
- if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ,
- LOCK_ENABLED_SOFTIRQS, "soft"))
- return 0;
- /*
- * Prove that the new dependency does not connect a softirq-safe-read
- * lock with a softirq-unsafe lock - to achieve this we search
- * the backwards-subgraph starting at <prev>, and the
- * forwards-subgraph starting at <next>:
- */
- if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ,
- LOCK_ENABLED_SOFTIRQS, "soft"))
- return 0;
-#endif
- /*
* For recursive read-locks we do all the dependency checks,
* but we dont store read-triggered dependencies (only
* write-triggered dependencies). This ensures that only the
@@ -1096,227 +1318,10 @@ out_bug:
return 0;
}
-#endif
-
-/*
- * Is this the address of a static object:
- */
-static int static_obj(void *obj)
-{
- unsigned long start = (unsigned long) &_stext,
- end = (unsigned long) &_end,
- addr = (unsigned long) obj;
-#ifdef CONFIG_SMP
- int i;
-#endif
-
- /*
- * static variable?
- */
- if ((addr >= start) && (addr < end))
- return 1;
-
-#ifdef CONFIG_SMP
- /*
- * percpu var?
- */
- for_each_possible_cpu(i) {
- start = (unsigned long) &__per_cpu_start + per_cpu_offset(i);
- end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM
- + per_cpu_offset(i);
-
- if ((addr >= start) && (addr < end))
- return 1;
- }
-#endif
-
- /*
- * module var?
- */
- return is_module_address(addr);
-}
-
-/*
- * To make lock name printouts unique, we calculate a unique
- * class->name_version generation counter:
- */
-static int count_matching_names(struct lock_class *new_class)
-{
- struct lock_class *class;
- int count = 0;
-
- if (!new_class->name)
- return 0;
-
- list_for_each_entry(class, &all_lock_classes, lock_entry) {
- if (new_class->key - new_class->subclass == class->key)
- return class->name_version;
- if (class->name && !strcmp(class->name, new_class->name))
- count = max(count, class->name_version);
- }
-
- return count + 1;
-}
-
-/*
- * Register a lock's class in the hash-table, if the class is not present
- * yet. Otherwise we look it up. We cache the result in the lock object
- * itself, so actual lookup of the hash should be once per lock object.
- */
-static inline struct lock_class *
-look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
-{
- struct lockdep_subclass_key *key;
- struct list_head *hash_head;
- struct lock_class *class;
-
-#ifdef CONFIG_DEBUG_LOCKDEP
- /*
- * If the architecture calls into lockdep before initializing
- * the hashes then we'll warn about it later. (we cannot printk
- * right now)
- */
- if (unlikely(!lockdep_initialized)) {
- lockdep_init();
- lockdep_init_error = 1;
- }
-#endif
-
- /*
- * Static locks do not have their class-keys yet - for them the key
- * is the lock object itself:
- */
- if (unlikely(!lock->key))
- lock->key = (void *)lock;
-
- /*
- * NOTE: the class-key must be unique. For dynamic locks, a static
- * lock_class_key variable is passed in through the mutex_init()
- * (or spin_lock_init()) call - which acts as the key. For static
- * locks we use the lock object itself as the key.
- */
- BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(struct lock_class));
-
- key = lock->key->subkeys + subclass;
-
- hash_head = classhashentry(key);
-
- /*
- * We can walk the hash lockfree, because the hash only
- * grows, and we are careful when adding entries to the end:
- */
- list_for_each_entry(class, hash_head, hash_entry)
- if (class->key == key)
- return class;
-
- return NULL;
-}
-
-/*
- * Register a lock's class in the hash-table, if the class is not present
- * yet. Otherwise we look it up. We cache the result in the lock object
- * itself, so actual lookup of the hash should be once per lock object.
- */
-static inline struct lock_class *
-register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
-{
- struct lockdep_subclass_key *key;
- struct list_head *hash_head;
- struct lock_class *class;
- unsigned long flags;
-
- class = look_up_lock_class(lock, subclass);
- if (likely(class))
- return class;
-
- /*
- * Debug-check: all keys must be persistent!
- */
- if (!static_obj(lock->key)) {
- debug_locks_off();
- printk("INFO: trying to register non-static key.\n");
- printk("the code is fine but needs lockdep annotation.\n");
- printk("turning off the locking correctness validator.\n");
- dump_stack();
- return NULL;
- }
-
- key = lock->key->subkeys + subclass;
- hash_head = classhashentry(key);
-
- raw_local_irq_save(flags);
- if (!graph_lock()) {
- raw_local_irq_restore(flags);
- return NULL;
- }
- /*
- * We have to do the hash-walk again, to avoid races
- * with another CPU:
- */
- list_for_each_entry(class, hash_head, hash_entry)
- if (class->key == key)
- goto out_unlock_set;
- /*
- * Allocate a new key from the static array, and add it to
- * the hash:
- */
- if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
- if (!debug_locks_off_graph_unlock()) {
- raw_local_irq_restore(flags);
- return NULL;
- }
- raw_local_irq_restore(flags);
-
- printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
- printk("turning off the locking correctness validator.\n");
- return NULL;
- }
- class = lock_classes + nr_lock_classes++;
- debug_atomic_inc(&nr_unused_locks);
- class->key = key;
- class->name = lock->name;
- class->subclass = subclass;
- INIT_LIST_HEAD(&class->lock_entry);
- INIT_LIST_HEAD(&class->locks_before);
- INIT_LIST_HEAD(&class->locks_after);
- class->name_version = count_matching_names(class);
- /*
- * We use RCU's safe list-add method to make
- * parallel walking of the hash-list safe:
- */
- list_add_tail_rcu(&class->hash_entry, hash_head);
-
- if (verbose(class)) {
- graph_unlock();
- raw_local_irq_restore(flags);
-
- printk("\nnew class %p: %s", class->key, class->name);
- if (class->name_version > 1)
- printk("#%d", class->name_version);
- printk("\n");
- dump_stack();
-
- raw_local_irq_save(flags);
- if (!graph_lock()) {
- raw_local_irq_restore(flags);
- return NULL;
- }
- }
-out_unlock_set:
- graph_unlock();
- raw_local_irq_restore(flags);
-
- if (!subclass || force)
- lock->class_cache = class;
-
- if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
- return NULL;
-
- return class;
-}
+unsigned long nr_lock_chains;
+static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
-#ifdef CONFIG_PROVE_LOCKING
/*
* Look up a dependency chain. If the key is not present yet then
* add it and return 1 - in this case the new dependency chain is
@@ -1376,21 +1381,71 @@ cache_hit:
chain->chain_key = chain_key;
list_add_tail_rcu(&chain->entry, hash_head);
debug_atomic_inc(&chain_lookup_misses);
-#ifdef CONFIG_TRACE_IRQFLAGS
- if (current->hardirq_context)
- nr_hardirq_chains++;
- else {
- if (current->softirq_context)
- nr_softirq_chains++;
- else
- nr_process_chains++;
- }
-#else
- nr_process_chains++;
-#endif
+ inc_chains();
+
+ return 1;
+}
+
+static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
+ struct held_lock *hlock, int chain_head)
+{
+ /*
+ * Trylock needs to maintain the stack of held locks, but it
+ * does not add new dependencies, because trylock can be done
+ * in any order.
+ *
+ * We look up the chain_key and do the O(N^2) check and update of
+ * the dependencies only if this is a new dependency chain.
+ * (If lookup_chain_cache() returns with 1 it acquires
+ * graph_lock for us)
+ */
+ if (!hlock->trylock && (hlock->check == 2) &&
+ lookup_chain_cache(curr->curr_chain_key, hlock->class)) {
+ /*
+ * Check whether last held lock:
+ *
+ * - is irq-safe, if this lock is irq-unsafe
+ * - is softirq-safe, if this lock is hardirq-unsafe
+ *
+ * And check whether the new lock's dependency graph
+ * could lead back to the previous lock.
+ *
+ * any of these scenarios could lead to a deadlock. If
+ * All validations
+ */
+ int ret = check_deadlock(curr, hlock, lock, hlock->read);
+
+ if (!ret)
+ return 0;
+ /*
+ * Mark recursive read, as we jump over it when
+ * building dependencies (just like we jump over
+ * trylock entries):
+ */
+ if (ret == 2)
+ hlock->read = 2;
+ /*
+ * Add dependency only if this lock is not the head
+ * of the chain, and if it's not a secondary read-lock:
+ */
+ if (!chain_head && ret != 2)
+ if (!check_prevs_add(curr, hlock))
+ return 0;
+ graph_unlock();
+ } else
+ /* after lookup_chain_cache(): */
+ if (unlikely(!debug_locks))
+ return 0;
return 1;
}
+#else
+static inline int validate_chain(struct task_struct *curr,
+ struct lockdep_map *lock, struct held_lock *hlock,
+ int chain_head)
+{
+ return 1;
+}
#endif
/*
@@ -1436,6 +1491,57 @@ static void check_chain_key(struct task_struct *curr)
#endif
}
+static int
+print_usage_bug(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
+{
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ return 0;
+
+ printk("\n=================================\n");
+ printk( "[ INFO: inconsistent lock state ]\n");
+ print_kernel_version();
+ printk( "---------------------------------\n");
+
+ printk("inconsistent {%s} -> {%s} usage.\n",
+ usage_str[prev_bit], usage_str[new_bit]);
+
+ printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
+ curr->comm, curr->pid,
+ trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
+ trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
+ trace_hardirqs_enabled(curr),
+ trace_softirqs_enabled(curr));
+ print_lock(this);
+
+ printk("{%s} state was registered at:\n", usage_str[prev_bit]);
+ print_stack_trace(this->class->usage_traces + prev_bit, 1);
+
+ print_irqtrace_events(curr);
+ printk("\nother info that might help us debug this:\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+/*
+ * Print out an error if an invalid bit is set:
+ */
+static inline int
+valid_state(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
+{
+ if (unlikely(this->class->usage_mask & (1 << bad_bit)))
+ return print_usage_bug(curr, this, bad_bit, new_bit);
+ return 1;
+}
+
+static int mark_lock(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit);
+
#ifdef CONFIG_TRACE_IRQFLAGS
/*
@@ -1529,90 +1635,30 @@ void print_irqtrace_events(struct task_struct *curr)
print_ip_sym(curr->softirq_disable_ip);
}
-#endif
-
-static int
-print_usage_bug(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
+static int hardirq_verbose(struct lock_class *class)
{
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- printk("\n=================================\n");
- printk( "[ INFO: inconsistent lock state ]\n");
- print_kernel_version();
- printk( "---------------------------------\n");
-
- printk("inconsistent {%s} -> {%s} usage.\n",
- usage_str[prev_bit], usage_str[new_bit]);
-
- printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
- curr->comm, curr->pid,
- trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
- trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
- trace_hardirqs_enabled(curr),
- trace_softirqs_enabled(curr));
- print_lock(this);
-
- printk("{%s} state was registered at:\n", usage_str[prev_bit]);
- print_stack_trace(this->class->usage_traces + prev_bit, 1);
-
- print_irqtrace_events(curr);
- printk("\nother info that might help us debug this:\n");
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
+#if HARDIRQ_VERBOSE
+ return class_filter(class);
+#endif
return 0;
}
-/*
- * Print out an error if an invalid bit is set:
- */
-static inline int
-valid_state(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
+static int softirq_verbose(struct lock_class *class)
{
- if (unlikely(this->class->usage_mask & (1 << bad_bit)))
- return print_usage_bug(curr, this, bad_bit, new_bit);
- return 1;
+#if SOFTIRQ_VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
}
#define STRICT_READ_CHECKS 1
-/*
- * Mark a lock with a usage bit, and validate the state transition:
- */
-static int mark_lock(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit)
+static int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit)
{
- unsigned int new_mask = 1 << new_bit, ret = 1;
-
- /*
- * If already set then do not dirty the cacheline,
- * nor do any checks:
- */
- if (likely(this->class->usage_mask & new_mask))
- return 1;
+ int ret = 1;
- if (!graph_lock())
- return 0;
- /*
- * Make sure we didnt race:
- */
- if (unlikely(this->class->usage_mask & new_mask)) {
- graph_unlock();
- return 1;
- }
-
- this->class->usage_mask |= new_mask;
-
- if (!save_trace(this->class->usage_traces + new_bit))
- return 0;
-
- switch (new_bit) {
-#ifdef CONFIG_TRACE_IRQFLAGS
+ switch(new_bit) {
case LOCK_USED_IN_HARDIRQ:
if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
return 0;
@@ -1771,37 +1817,14 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
if (softirq_verbose(this->class))
ret = 2;
break;
-#endif
- case LOCK_USED:
- /*
- * Add it to the global list of classes:
- */
- list_add_tail_rcu(&this->class->lock_entry, &all_lock_classes);
- debug_atomic_dec(&nr_unused_locks);
- break;
default:
- if (!debug_locks_off_graph_unlock())
- return 0;
WARN_ON(1);
- return 0;
- }
-
- graph_unlock();
-
- /*
- * We must printk outside of the graph_lock:
- */
- if (ret == 2) {
- printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
- print_lock(this);
- print_irqtrace_events(curr);
- dump_stack();
+ break;
}
return ret;
}
-#ifdef CONFIG_TRACE_IRQFLAGS
/*
* Mark all held locks with a usage bit:
*/
@@ -1984,9 +2007,176 @@ void trace_softirqs_off(unsigned long ip)
debug_atomic_inc(&redundant_softirqs_off);
}
+static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
+{
+ /*
+ * If non-trylock use in a hardirq or softirq context, then
+ * mark the lock as used in these contexts:
+ */
+ if (!hlock->trylock) {
+ if (hlock->read) {
+ if (curr->hardirq_context)
+ if (!mark_lock(curr, hlock,
+ LOCK_USED_IN_HARDIRQ_READ))
+ return 0;
+ if (curr->softirq_context)
+ if (!mark_lock(curr, hlock,
+ LOCK_USED_IN_SOFTIRQ_READ))
+ return 0;
+ } else {
+ if (curr->hardirq_context)
+ if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
+ return 0;
+ if (curr->softirq_context)
+ if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
+ return 0;
+ }
+ }
+ if (!hlock->hardirqs_off) {
+ if (hlock->read) {
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_HARDIRQS_READ))
+ return 0;
+ if (curr->softirqs_enabled)
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_SOFTIRQS_READ))
+ return 0;
+ } else {
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_HARDIRQS))
+ return 0;
+ if (curr->softirqs_enabled)
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_SOFTIRQS))
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+static int separate_irq_context(struct task_struct *curr,
+ struct held_lock *hlock)
+{
+ unsigned int depth = curr->lockdep_depth;
+
+ /*
+ * Keep track of points where we cross into an interrupt context:
+ */
+ hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
+ curr->softirq_context;
+ if (depth) {
+ struct held_lock *prev_hlock;
+
+ prev_hlock = curr->held_locks + depth-1;
+ /*
+ * If we cross into another context, reset the
+ * hash key (this also prevents the checking and the
+ * adding of the dependency to 'prev'):
+ */
+ if (prev_hlock->irq_context != hlock->irq_context)
+ return 1;
+ }
+ return 0;
+}
+
+#else
+
+static inline
+int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit)
+{
+ WARN_ON(1);
+ return 1;
+}
+
+static inline int mark_irqflags(struct task_struct *curr,
+ struct held_lock *hlock)
+{
+ return 1;
+}
+
+static inline int separate_irq_context(struct task_struct *curr,
+ struct held_lock *hlock)
+{
+ return 0;
+}
+
#endif
/*
+ * Mark a lock with a usage bit, and validate the state transition:
+ */
+static int mark_lock(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit)
+{
+ unsigned int new_mask = 1 << new_bit, ret = 1;
+
+ /*
+ * If already set then do not dirty the cacheline,
+ * nor do any checks:
+ */
+ if (likely(this->class->usage_mask & new_mask))
+ return 1;
+
+ if (!graph_lock())
+ return 0;
+ /*
+ * Make sure we didnt race:
+ */
+ if (unlikely(this->class->usage_mask & new_mask)) {
+ graph_unlock();
+ return 1;
+ }
+
+ this->class->usage_mask |= new_mask;
+
+ if (!save_trace(this->class->usage_traces + new_bit))
+ return 0;
+
+ switch (new_bit) {
+ case LOCK_USED_IN_HARDIRQ:
+ case LOCK_USED_IN_SOFTIRQ:
+ case LOCK_USED_IN_HARDIRQ_READ:
+ case LOCK_USED_IN_SOFTIRQ_READ:
+ case LOCK_ENABLED_HARDIRQS:
+ case LOCK_ENABLED_SOFTIRQS:
+ case LOCK_ENABLED_HARDIRQS_READ:
+ case LOCK_ENABLED_SOFTIRQS_READ:
+ ret = mark_lock_irq(curr, this, new_bit);
+ if (!ret)
+ return 0;
+ break;
+ case LOCK_USED:
+ /*
+ * Add it to the global list of classes:
+ */
+ list_add_tail_rcu(&this->class->lock_entry, &all_lock_classes);
+ debug_atomic_dec(&nr_unused_locks);
+ break;
+ default:
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+ WARN_ON(1);
+ return 0;
+ }
+
+ graph_unlock();
+
+ /*
+ * We must printk outside of the graph_lock:
+ */
+ if (ret == 2) {
+ printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
+ print_lock(this);
+ print_irqtrace_events(curr);
+ dump_stack();
+ }
+
+ return ret;
+}
+
+/*
* Initialize a lock instance's lock-class mapping info:
*/
void lockdep_init_map(struct lockdep_map *lock, const char *name,
@@ -2082,56 +2272,13 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
hlock->check = check;
hlock->hardirqs_off = hardirqs_off;
- if (check != 2)
- goto out_calc_hash;
-#ifdef CONFIG_TRACE_IRQFLAGS
- /*
- * If non-trylock use in a hardirq or softirq context, then
- * mark the lock as used in these contexts:
- */
- if (!trylock) {
- if (read) {
- if (curr->hardirq_context)
- if (!mark_lock(curr, hlock,
- LOCK_USED_IN_HARDIRQ_READ))
- return 0;
- if (curr->softirq_context)
- if (!mark_lock(curr, hlock,
- LOCK_USED_IN_SOFTIRQ_READ))
- return 0;
- } else {
- if (curr->hardirq_context)
- if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
- return 0;
- if (curr->softirq_context)
- if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
- return 0;
- }
- }
- if (!hardirqs_off) {
- if (read) {
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_HARDIRQS_READ))
- return 0;
- if (curr->softirqs_enabled)
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_SOFTIRQS_READ))
- return 0;
- } else {
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_HARDIRQS))
- return 0;
- if (curr->softirqs_enabled)
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_SOFTIRQS))
- return 0;
- }
- }
-#endif
+ if (check == 2 && !mark_irqflags(curr, hlock))
+ return 0;
+
/* mark it as used: */
if (!mark_lock(curr, hlock, LOCK_USED))
return 0;
-out_calc_hash:
+
/*
* Calculate the chain hash: it's the combined has of all the
* lock keys along the dependency chain. We save the hash value
@@ -2154,77 +2301,15 @@ out_calc_hash:
}
hlock->prev_chain_key = chain_key;
-
-#ifdef CONFIG_TRACE_IRQFLAGS
- /*
- * Keep track of points where we cross into an interrupt context:
- */
- hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
- curr->softirq_context;
- if (depth) {
- struct held_lock *prev_hlock;
-
- prev_hlock = curr->held_locks + depth-1;
- /*
- * If we cross into another context, reset the
- * hash key (this also prevents the checking and the
- * adding of the dependency to 'prev'):
- */
- if (prev_hlock->irq_context != hlock->irq_context) {
- chain_key = 0;
- chain_head = 1;
- }
+ if (separate_irq_context(curr, hlock)) {
+ chain_key = 0;
+ chain_head = 1;
}
-#endif
chain_key = iterate_chain_key(chain_key, id);
curr->curr_chain_key = chain_key;
- /*
- * Trylock needs to maintain the stack of held locks, but it
- * does not add new dependencies, because trylock can be done
- * in any order.
- *
- * We look up the chain_key and do the O(N^2) check and update of
- * the dependencies only if this is a new dependency chain.
- * (If lookup_chain_cache() returns with 1 it acquires
- * graph_lock for us)
- */
- if (!trylock && (check == 2) && lookup_chain_cache(chain_key, class)) {
- /*
- * Check whether last held lock:
- *
- * - is irq-safe, if this lock is irq-unsafe
- * - is softirq-safe, if this lock is hardirq-unsafe
- *
- * And check whether the new lock's dependency graph
- * could lead back to the previous lock.
- *
- * any of these scenarios could lead to a deadlock. If
- * All validations
- */
- int ret = check_deadlock(curr, hlock, lock, read);
-
- if (!ret)
- return 0;
- /*
- * Mark recursive read, as we jump over it when
- * building dependencies (just like we jump over
- * trylock entries):
- */
- if (ret == 2)
- hlock->read = 2;
- /*
- * Add dependency only if this lock is not the head
- * of the chain, and if it's not a secondary read-lock:
- */
- if (!chain_head && ret != 2)
- if (!check_prevs_add(curr, hlock))
- return 0;
- graph_unlock();
- } else
- /* after lookup_chain_cache(): */
- if (unlikely(!debug_locks))
- return 0;
+ if (!validate_chain(curr, lock, hlock, chain_head))
+ return 0;
curr->lockdep_depth++;
check_chain_key(curr);
diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c
index 58f35e586ee..2fde34127e2 100644
--- a/kernel/lockdep_proc.c
+++ b/kernel/lockdep_proc.c
@@ -271,8 +271,10 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
if (nr_list_entries)
factor = sum_forward_deps / nr_list_entries;
+#ifdef CONFIG_PROVE_LOCKING
seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
nr_lock_chains, MAX_LOCKDEP_CHAINS);
+#endif
#ifdef CONFIG_TRACE_IRQFLAGS
seq_printf(m, " in-hardirq chains: %11u\n",