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KERN_OPERATION_TIMED_OUT
A timeout while waiting on a kernel operation
KERN_OPERATION_TIMED_OUT is a thread-oriented Mach timeout; XNU names semaphore_wait as an example. It is not an HTTP timeout, a DNS lookup failure, or a generic network condition. The wait completed unsuccessfully because its time limit elapsed before the expected synchronization event occurred.
A timeout is only meaningful with the waited-for condition, the deadline, and the object lifetime. A semaphore can remain valid while a wait expires; if it was destroyed, the more specific KERN_SEMAPHORE_DESTROYED applies.
What to inspect
- Record the specific wait primitive, timeout value, and clock/deadline convention.
- Identify which producer or owner was expected to signal the condition.
- Determine whether the wait may be safely retried and whether a duplicate action would be harmful.
- Inspect queue depth, lock contention, and shutdown events that explain why progress did not occur.
References
- Apple XNU: kern_return.h
- Apple Kernel Programming Guide: Mach semaphores and timeouts
- Mach Kernel Interface Reference: semaphore_wait
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