I think there's also a problem with multiple tasks sharing the same lock owner. So, all locks are exclusive locks for the same range. We have four tasks. Tasks 1 and 4 share the same owner, the others' owners are distinct. - Task 1 gets a lock. - Task 2 gets a conflicting lock. - Task 3 gets another conflicting lock. So now we the tree is 3->2->1. - Task 1's lock is released. - Before task 2 is scheduled, task 4 acquires a new lock. - Task 2 waits on task 4's lock, we now have 3->2->4. Task 3 shouldn't be waiting--the lock it's requesting has the same owner as the lock task 4 holds--but we fail to wake up task 3. --b.
