diff --git a/src/agentex/lib/core/tracing/tracing_processor_manager.py b/src/agentex/lib/core/tracing/tracing_processor_manager.py
index 5227e891c..a1b6a3a37 100644
--- a/src/agentex/lib/core/tracing/tracing_processor_manager.py
+++ b/src/agentex/lib/core/tracing/tracing_processor_manager.py
@@ -4,7 +4,7 @@
 import logging
 import threading
 from typing import TYPE_CHECKING
-from threading import Lock
+from threading import RLock
 
 from agentex.lib.types.tracing import TracingProcessorConfig
 from agentex.lib.core.tracing.processors.sgp_tracing_processor import (
@@ -36,7 +36,7 @@ def __init__(self):
         # Cache for processors
         self.sync_processors: list[SyncTracingProcessor] = []
         self.async_processors: list[AsyncTracingProcessor] = []
-        self.lock = Lock()
+        self.lock = RLock()
         self._agentex_registered = False
 
     def _ensure_agentex_registered(self):
diff --git a/tests/lib/core/tracing/test_tracing_processor_manager.py b/tests/lib/core/tracing/test_tracing_processor_manager.py
new file mode 100644
index 000000000..d17ac6581
--- /dev/null
+++ b/tests/lib/core/tracing/test_tracing_processor_manager.py
@@ -0,0 +1,64 @@
+from __future__ import annotations
+
+import threading
+from typing import Any, cast
+from dataclasses import dataclass
+
+from agentex.lib.core.tracing.tracing_processor_manager import TracingProcessorManager
+
+
+@dataclass
+class _FakeConfig:
+    type: str = "fake"
+
+
+class _FakeProcessor:
+    def __init__(self, config: Any) -> None:
+        self.config = config
+
+
+def _manager() -> TracingProcessorManager:
+    manager = TracingProcessorManager()
+    manager.sync_config_registry["fake"] = cast(Any, _FakeProcessor)
+    manager.async_config_registry["fake"] = cast(Any, _FakeProcessor)
+    return manager
+
+
+REGISTRATION_DEADLINE_SECONDS = 5.0
+
+
+def _finishes(target: Any, timeout: float = REGISTRATION_DEADLINE_SECONDS) -> bool:
+    errors: list[BaseException] = []
+
+    def _run() -> None:
+        try:
+            target()
+        except BaseException as exc:
+            errors.append(exc)
+
+    thread = threading.Thread(target=_run, daemon=True)
+    thread.start()
+    thread.join(timeout)
+    if errors:
+        raise errors[0]
+    return not thread.is_alive()
+
+
+def test_set_processor_configs_registers_every_config_without_deadlocking() -> None:
+    manager = _manager()
+    configs = [_FakeConfig(), _FakeConfig()]
+
+    finished = _finishes(lambda: manager.set_processor_configs(cast(Any, configs)))
+
+    assert finished, "set_processor_configs blocked on the manager's own lock"
+    assert [cast(Any, p).config for p in manager.get_sync_processors()] == configs
+    assert [cast(Any, p).config for p in manager.get_async_processors()] == configs
+
+
+def test_add_processor_config_still_registers_one_pair() -> None:
+    manager = _manager()
+
+    manager.add_processor_config(cast(Any, _FakeConfig()))
+
+    assert len(manager.get_sync_processors()) == 1
+    assert len(manager.get_async_processors()) == 1