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ERROR_INVALID_AT_INTERRUPT_TIME
What ERROR_INVALID_AT_INTERRUPT_TIME means
The requested exclusive semaphore operation is invalid at interrupt time or from an execution context that cannot wait. This is a context-contract error. A routine attempted synchronization that may block while running at an interrupt-sensitive level or equivalent non-waitable context. It is most relevant to low-level, legacy, or emulated execution environments.
Common causes
- A callback running at elevated execution level calls a potentially blocking routine
- Driver or compatibility code performs user-mode style synchronization in an interrupt path
- A helper function is reused without documenting its waitability requirements
- Deferred work was not queued before entering the blocking section
How to investigate
- Capture the execution level or callback type at the failing call
- Trace the call chain to find the first routine that introduced a waitable operation
- Separate interrupt-time work from deferred worker-thread processing
- Use verifier or checked instrumentation appropriate to the component type
Developer guidance
Keep interrupt-sensitive paths bounded and nonblocking. Record minimal state, queue deferred work, and perform semaphore acquisition from a context where waiting is legal.
Administrator and support guidance
This result normally requires a code correction. Restarting can clear the immediate incident but cannot make an invalid execution context safe.
How this code differs from related results
The code is about where the operation runs, not whether the semaphore name, handle, or access rights are valid.
References
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