NationalSecurityAgency/ghidra · error · RuntimeError

No memory mapper

Error message

No memory mapper

What it means

Raised by Extra.require_mm when the trace's memory_mapper has not been set. The memory mapper translates between Ghidra Address objects and x64dbg offsets; it is initialized during start_trace via compute_memory_mapper. Any memory operation that calls require_mm before start_trace completes will hit this guard.

Source

Thrown at Ghidra/Debug/Debugger-agent-x64dbg/src/main/py/src/ghidraxdbg/commands.py:102

class ErrorWithCode(Exception):

    def __init__(self, code: int) -> None:
        self.code = code

    def __str__(self) -> str:
        return repr(self.code)


class Extra(object):
    def __init__(self) -> None:
        self.memory_mapper: Optional[arch.DefaultMemoryMapper] = None
        self.register_mapper: Optional[arch.DefaultRegisterMapper] = None

    def require_mm(self) -> arch.DefaultMemoryMapper:
        if self.memory_mapper is None:
            raise RuntimeError("No memory mapper")
        return self.memory_mapper

    def require_rm(self) -> arch.DefaultRegisterMapper:
        if self.register_mapper is None:
            raise RuntimeError("No register mapper")
        return self.register_mapper


class State(object):

    def __init__(self) -> None:
        self.reset_client()

    def require_client(self) -> Client:
        if self.client is None:
            raise RuntimeError("Not connected")
        return self.client

View on GitHub (pinned to d5f144c24d)

Solutions

1. Ensure 'ghidra trace start' (or start_trace) completes successfully before issuing memory commands.
2. Verify start_trace ran without errors (check for schema.xml load failures).
3. Call STATE.trace.extra.memory_mapper = arch.compute_memory_mapper(language) if mappers are missing.

Example fix

# before: memory op before trace start
STATE.require_trace().extra.require_mm()  # mapper is None

# after: start trace first
start_trace(compute_name())
mm = STATE.trace.extra.require_mm()  # mapper now set

extra = STATE.trace.extra if STATE.trace else None
if extra is None or extra.memory_mapper is None:
    raise RuntimeError("Memory mapper not initialized; run 'ghidra trace start' first")

def has_memory_mapper(extra: 'Extra') -> bool:
    return extra is not None and extra.memory_mapper is not None

try:
    mm = STATE.trace.extra.require_mm()
except RuntimeError:
    # trace not started or mapper not set; start trace to initialize
    start_trace(compute_name())
    mm = STATE.trace.extra.require_mm()

When it happens

Trigger: A trace method calls STATE.trace.extra.require_mm() (directly or via a memory operation) before start_trace has set memory_mapper. This happens if commands are issued before 'ghidra trace start' completes or if the trace object's extra was not properly initialized.

Common situations: The user issued memory read/write commands before starting a trace. start_trace failed partway through (e.g. schema.xml not found) leaving mappers unset. The trace was created manually without going through start_trace.

Related errors

• No register mapper
• Not connected
• No trace active
• Already connected
• Trace already started

AI-assisted analysis of NationalSecurityAgency/ghidra@d5f144c24d (2026-08-14). Data as JSON: /api/errors/cce19e09a03638e8. Report an issue: GitHub.