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STATUS_PORT_ALREADY_HAS_COMPLETION_LIST
The ALPC completion-list association is already established
A completion list is a port-level delivery resource, not a per-message option. Registration allocates shared bookkeeping and binds its lifetime to the port configuration. A second registration usually indicates duplicate initialization, competing owners, or an attempted resize performed without first dismantling the existing association.
Do not overwrite the first list pointer or free its storage while callbacks can still publish entries. Initialization and teardown must be serialized with message producers and consumers, especially when a service restarts only part of its communication subsystem.
What to inspect
- Find the first successful completion-list association and identify the component that owns its memory.
- Protect initialization with a one-time state transition rather than a check-then-register race.
- Drain consumers and stop producers before releasing completion-list storage.
- Treat reconfiguration as port recreation unless the native contract explicitly supports an in-place change.
References
- Microsoft Open Specifications: NTSTATUS values
- System Informer PHNT: native ALPC definitions
- Microsoft Windows SDK metadata: ntstatus.h
- Microsoft: pooled threads and callback environments
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