On Thu, Jan 09, 2014 at 12:15:16PM +0100, Peter Zijlstra wrote:
> @@ -276,8 +292,14 @@ extern void lockdep_on(void);
> * to lockdep:
> */
>
> -extern void lockdep_init_map(struct lockdep_map *lock, const char *name,
> - struct lock_class_key *key, int subclass);
> +extern void lockdep_init_map_wait(struct lockdep_map *lock, const char *name,
> + struct lock_class_key *key, int subclass, short inner);
> +
> +static inline void lockdep_init_map(struct lockdep_map *lock, const char
> *name,
> + struct lock_class_key *key, int subclass)
> +{
> + lockdep_init_map_wait(lock, name, key, subclass, LD_WAIT_INV);
> +}
>
> /*
> * To initialize a lockdep_map statically use this macro.
Realized that the above destroys existing wait types for
lockdep_set_*(), so update those to preserve the wait_types.
At which point a trylock triggered a wait_type violation which is of
course a validation mistake, so ignore trylocks.
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -314,15 +314,21 @@ static inline void lockdep_init_map(stru
* of dependencies wrong: they are either too broad (they need a class-split)
* or they are too narrow (they suffer from a false class-split):
*/
-#define lockdep_set_class(lock, key) \
- lockdep_init_map(&(lock)->dep_map, #key, key, 0)
-#define lockdep_set_class_and_name(lock, key, name) \
- lockdep_init_map(&(lock)->dep_map, name, key, 0)
-#define lockdep_set_class_and_subclass(lock, key, sub) \
- lockdep_init_map(&(lock)->dep_map, #key, key, sub)
-#define lockdep_set_subclass(lock, sub) \
- lockdep_init_map(&(lock)->dep_map, #lock, \
- (lock)->dep_map.key, sub)
+#define lockdep_set_class(lock, key) \
+ lockdep_init_map_wait(&(lock)->dep_map, #key, key, 0, \
+ (lock)->dep_map.wait_type_inner)
+
+#define lockdep_set_class_and_name(lock, key, name) \
+ lockdep_init_map_wait(&(lock)->dep_map, name, key, 0, \
+ (lock)->dep_map.wait_type_inner)
+
+#define lockdep_set_class_and_subclass(lock, key, sub) \
+ lockdep_init_map_wait(&(lock)->dep_map, #key, key, sub, \
+ (lock)->dep_map.wait_type_inner)
+
+#define lockdep_set_subclass(lock, sub)
\
+ lockdep_init_map_wait(&(lock)->dep_map, #lock, (lock)->dep_map.key,
sub,\
+ (lock)->dep_map.wait_type_inner)
#define lockdep_set_novalidate_class(lock) \
lockdep_set_class(lock, &__lockdep_no_validate__)
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -3092,14 +3092,14 @@ print_lock_invalid_wait_context(struct t
* Therefore we must look for the strictest environment in the lock stack and
* compare that to the lock we're trying to acquire.
*/
-static int check_context(struct task_struct *curr, struct held_lock *next)
+static int check_wait_context(struct task_struct *curr, struct held_lock *next)
{
short next_inner = hlock_class(next)->wait_type_inner;
short next_outer = hlock_class(next)->wait_type_outer;
short curr_inner = LD_WAIT_MAX;
int depth;
- if (!curr->lockdep_depth || !next_inner)
+ if (!curr->lockdep_depth || !next_inner || next->trylock)
return 0;
if (!next_outer)
@@ -3111,8 +3111,10 @@ static int check_context(struct task_str
if (prev_inner) {
/*
- * we can have a bigger inner than a previous one
+ * We can have a bigger inner than a previous one
* when outer is smaller than inner, as with RCU.
+ *
+ * Also due to trylocks.
*/
curr_inner = min(curr_inner, prev_inner);
}
@@ -3226,7 +3228,7 @@ static int __lock_acquire(struct lockdep
hlock->holdtime_stamp = lockstat_clock();
#endif
- if (check_context(curr, hlock))
+ if (check_wait_context(curr, hlock))
return 0;
if (check == 2 && !mark_irqflags(curr, hlock))
--
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