Occurs when a task does not release a lock before the task ends.
|
ID |
Code Location |
Description |
|---|---|---|
|
1 |
Allocation site |
If present, represents the location and associated call stack when the lock was created. |
|
2 |
Lock owned |
If present, represents the location and its associated call stack when the lock was last acquired. |
|
3 |
Parallel site |
If present, represents the location and associated call stack of the site-begin annotation of the parallel site containing the task that acquired the lock. |
Example
void problem()
{
ANNOTATE_SITE_BEGIN(dangle_site1); // Parallel site
ANNOTATE_TASK_BEGIN(task1);
ANNOTATE_LOCK_ACQUIRE(&dangle); // Lock owned
ANNOTATE_TASK_END();
// ...
ANNOTATE_SITE_END();
}
In this example:
-
There is a parallel site that contains a task.
-
The lock is acquired in the task.
-
The lock is not released before the end of the task - the ANNOTATE_LOCK_RELEASE() annotation is missing.
Possible Correction Strategies
-
Make sure that an ANNOTATE_LOCK_RELEASE(address) annotation is executed on every flow path from an ANNOTATE_LOCK_ACQUIRE(address) annotation to the end of the task. If a code region has multiple exit flow paths, make sure the lock is released on all the paths.
Consider putting the lock-acquire and lock-release in the constructor and destructor of a static object, so that lock release happens automatically.
Consider putting a lock release in an exception handler if a the locked region might exit from an exception.
For more information about lock annotations, see the help topics below.