NationalSecurityAgency/ghidra · error · CodeUnitInsertionException

Code units cannot overlap

Error message

Code units cannot overlap

What it means

Thrown early in DBTraceDefinedDataView.create() when the start address is already occupied by a defined unit at the requested startSnap — the undefinedData view does not cover the single-byte range at (startSnap, address). This is the initial overlap check performed before data type resolution; it catches the case where another instruction or data unit already exists at the exact start address before any type processing happens.

Solutions

1. Delete the existing code unit at that address+snap before creating: codeUnit.delete() or disassembleClear().
2. Use a different address or snapshot range.
3. Check view.getContaining(startSnap, address) before creating and handle the conflict.

Example fix

// before
view.create(Lifespan.span(0, 10), address, platform, dataType); // address already defined

// after — clear existing unit first
CodeUnit existing = view.getContaining(0, address);
if (existing != null) {
    existing.delete();
}
view.create(Lifespan.span(0, 10), address, platform, dataType);

// Check if the start address is already defined before creating
long startSnap = lifespan.lmin();
if (!space.undefinedData.coversRange(Lifespan.at(startSnap),
        new AddressRangeImpl(address, address))) {
    // Address is occupied — clear or skip
    CodeUnit existing = view.getContaining(startSnap, address);
    if (existing != null) existing.delete();
}
view.create(lifespan, address, platform, dataType, length);

try {
    view.create(lifespan, address, platform, dataType, length);
} catch (CodeUnitInsertionException e) {
    if (e.getMessage().equals("Code units cannot overlap")) {
        CodeUnit existing = view.getContaining(lifespan.lmin(), address);
        if (existing != null) {
            existing.delete();
            view.create(lifespan, address, platform, dataType, length);
        }
    } else {
        throw e;
    }
}

When it happens

Trigger: Calling view.create() at an address+snap where an existing code unit (instruction or data) already starts or covers that address. The check space.undefinedData.coversRange(Lifespan.at(startSnap), [address, address]) fails because the address is already defined.

Common situations: Creating data at an address that already has an instruction; creating overlapping data units; not clearing old units before re-annotating; script that iterates and creates data without checking for conflicts.

Related errors

• Code units cannot overlap
• Length override of conflicts with code unit at , lifespan=
• Could unit would extend beyond address space
• Couldn't get requested bytes for CodeUnit
• Failed to resolve data length for

AI-assisted analysis of NationalSecurityAgency/ghidra@d5f144c24d (2026-08-14). Data as JSON: /api/errors/fe5532a6aee870db. Report an issue: GitHub.

Appendix: source

Thrown at Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/database/listing/DBTraceDefinedDataView.java:86

		return false;
	}

	@Override
	public DBTraceDataAdapter create(Lifespan lifespan, Address address, TracePlatform platform,
			DataType origType, int origLength) throws CodeUnitInsertionException {
		if (platform.getTrace() != getTrace() ||
			!(platform instanceof InternalTracePlatform iPlatform)) {
			throw new IllegalArgumentException("Platform is not part of this trace");
		}
		try (LockHold hold = LockHold.lock(space.lock.writeLock())) {
			DBTraceMemorySpace memSpace = space.trace.getMemoryManager().get(space.space, true);
			// NOTE: User-given length could be ignored....
			// Check start address first. After I know length, I can check for other existing units
			long startSnap = lifespan.lmin();
			if (!space.undefinedData.coversRange(Lifespan.at(startSnap),
				new AddressRangeImpl(address, address))) {
				// TODO: Figure out the conflicting unit?
				throw new CodeUnitInsertionException("Code units cannot overlap");
			}

			DataType dataType;
			int length;
			if (origType instanceof FactoryDataType) {
				MemBuffer buffer = memSpace.getBufferAt(startSnap, address);
				FactoryDataType fdt = (FactoryDataType) origType;
				dataType = fdt.getDataType(buffer);
				length = -1;
			}
			else {
				dataType = origType;
				length = origLength;
			}

			if (dataType == null) {
				throw new CodeUnitInsertionException("Failed to resolve data type");
			}

View on GitHub (pinned to d5f144c24d)