cuda.core: reject register() on a non-IPC memory resource

cuda_core/cuda/core/_memory/_ipc.pyx

@@ -268,6 +268,8 @@ cdef _MemPool MP_register(_MemPool self, uuid):
     existing = registry.get(uuid)
     if existing is not None:
         return existing
+    if not self.is_ipc_enabled:
+        raise RuntimeError("Memory resource is not IPC-enabled")
     assert self.uuid is None or self.uuid == uuid
     registry[uuid] = self
     self._ipc_data._alloc_handle._uuid = uuid

cuda_core/docs/source/release/1.2.0-notes.rst

@@ -73,6 +73,14 @@ Fixes and enhancements
   Windows, both ``ctypes.CFUNCTYPE`` and ``ctypes.WINFUNCTYPE`` are accepted.
   (`#2439 <https://github.com/NVIDIA/cuda-python/issues/2439>`__)
 
+- :meth:`DeviceMemoryResource.register` and
+  :meth:`PinnedMemoryResource.register` now raise ``RuntimeError`` when the
+  memory resource does not have IPC enabled. Previously they dereferenced a
+  ``None`` attribute and terminated the process with a segmentation fault, so
+  the call could not be guarded with ``try``. A rejected registration no longer
+  leaves an entry in the memory resource registry.
+  (`#2568 <https://github.com/NVIDIA/cuda-python/issues/2568>`__)
+
 Deprecation Notices
 -------------------
 

cuda_core/tests/memory_ipc/test_errors.py

@@ -4,6 +4,7 @@
 import multiprocessing
 import pickle
 import re
+import uuid
 
 import pytest
 from helpers.child_processes import child_timeout_sec, kill_subprocesses
@@ -51,6 +52,23 @@ def test_ipc_allocation_handle_rejects_negative_fd():
         IPCAllocationHandle._init(-1, None)
 
 
+@pytest.mark.human_authored
+def test_register_rejects_non_ipc_memory_resource():
+    """register() on a resource without IPC enabled raises instead of dereferencing None."""
+    device = Device()
+    device.set_current()
+    mr = DeviceMemoryResource(device)
+    assert not mr.is_ipc_enabled
+
+    key = uuid.uuid4()
+    with pytest.raises(RuntimeError, match="Memory resource is not IPC-enabled"):
+        mr.register(key)
+
+    # The rejected registration must not leave the resource in the registry.
+    with pytest.raises(RuntimeError, match=r"Memory resource [a-z0-9-]+ was not found"):
+        DeviceMemoryResource.from_registry(key)
+
+
 class ChildErrorHarness:
     """Test harness for checking errors in child processes. Subclasses override
     PARENT_ACTION, CHILD_ACTION, and ASSERT (see below for examples)."""