macOS kernel return 29 (KERN_INVALID_OBJECT): meaning and diagnosis

Status / error code:		Category:

Constant name:
Source:		Operating System:
Description: An external memory manager did not initialize a Mach memory object.

Could be also:
Constant	Type	OS
ERROR_WRITE_FAULT	Win32 error	Windows
ippStsWrongIntersectROI	Intel Ipp Status	Any
ESPIPE	errno	Any
NO_SPIN_LOCK_AVAILABLE	BugCheck Code	Windows

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KERN_INVALID_POLICY	KERN_ALREADY_WAITING

KERN_INVALID_OBJECT

KERN_INVALID_OBJECT is not a general “bad object handle” result. In XNU it specifically describes an external memory manager that failed to initialize a memory object. The status belongs to Mach's memory-object protocol, where a pager or memory manager cooperates with the kernel to provide data for virtual memory.

That context matters because ordinary application code normally works through higher-level memory APIs and may never see this return. When it does appear, the useful evidence is the memory-object lifecycle, the initialization handshake, and the pager-side failure—not a raw pointer passed by an unrelated client.

What to inspect

Identify the memory-object or pager implementation associated with the failing request.
Correlate the return with object creation, initialization, and any earlier pager error.
Separate this case from KERN_INVALID_ADDRESS and KERN_PROTECTION_FAILURE, which concern mappings in a task's address space.
Preserve the target task and memory-object port identities where they are safe to log.

References

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