lockdep: Introduce lockdep_assert_held()
Add a lockdep helper to validate that we indeed are the owner
of a lock.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 12aabfc..a6d5e5e 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -296,6 +296,10 @@
extern void lock_release(struct lockdep_map *lock, int nested,
unsigned long ip);
+#define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map)
+
+extern int lock_is_held(struct lockdep_map *lock);
+
extern void lock_set_class(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, unsigned int subclass,
unsigned long ip);
@@ -314,6 +318,8 @@
#define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
+#define lockdep_assert_held(l) WARN_ON(debug_locks && !lockdep_is_held(l))
+
#else /* !LOCKDEP */
static inline void lockdep_off(void)
@@ -358,6 +364,8 @@
#define lockdep_depth(tsk) (0)
+#define lockdep_assert_held(l) do { } while (0)
+
#endif /* !LOCKDEP */
#ifdef CONFIG_LOCK_STAT
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 4b6cebe..28914a5 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -3059,6 +3059,19 @@
check_chain_key(curr);
}
+static int __lock_is_held(struct lockdep_map *lock)
+{
+ struct task_struct *curr = current;
+ int i;
+
+ for (i = 0; i < curr->lockdep_depth; i++) {
+ if (curr->held_locks[i].instance == lock)
+ return 1;
+ }
+
+ return 0;
+}
+
/*
* Check whether we follow the irq-flags state precisely:
*/
@@ -3160,6 +3173,26 @@
}
EXPORT_SYMBOL_GPL(lock_release);
+int lock_is_held(struct lockdep_map *lock)
+{
+ unsigned long flags;
+ int ret = 0;
+
+ if (unlikely(current->lockdep_recursion))
+ return ret;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+
+ current->lockdep_recursion = 1;
+ ret = __lock_is_held(lock);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(lock_is_held);
+
void lockdep_set_current_reclaim_state(gfp_t gfp_mask)
{
current->lockdep_reclaim_gfp = gfp_mask;
diff --git a/kernel/sched.c b/kernel/sched.c
index 1b59e26..2c75f7d 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6609,6 +6609,8 @@
int resched = should_resched();
int ret = 0;
+ lockdep_assert_held(lock);
+
if (spin_needbreak(lock) || resched) {
spin_unlock(lock);
if (resched)