fix: avoid tilelang cuda runtime pollution (#30870)

test/registered/unit/distributed/test_cuda_wrapper.py

@@ -0,0 +1,38 @@
+import io
+
+import pytest
+
+from sglang.test.ci.ci_register import register_cuda_ci
+
+register_cuda_ci(est_time=2, stage="base-b", runner_config="1-gpu-small")
+
+from sglang.srt.distributed.device_communicators import cuda_wrapper
+
+
+def test_find_loaded_library_prefers_real_cudart_over_tilelang_stub(monkeypatch):
+    maps = """\
+7f000000-7f010000 r-xp 00000000 00:00 0 /site-packages/tilelang/lib/libcudart_stub.so
+7f020000-7f030000 r-xp 00000000 00:00 0 /cuda/lib64/libcudart.so.13
+"""
+
+    monkeypatch.setattr("builtins.open", lambda *args, **kwargs: io.StringIO(maps))
+
+    assert (
+        cuda_wrapper.find_loaded_library("libcudart") == "/cuda/lib64/libcudart.so.13"
+    )
+
+
+def test_find_loaded_library_strips_deleted_suffix(monkeypatch):
+    maps = """\
+7f020000-7f030000 r-xp 00000000 00:00 0 /cuda/lib64/libcudart.so.13 (deleted)
+"""
+
+    monkeypatch.setattr("builtins.open", lambda *args, **kwargs: io.StringIO(maps))
+
+    assert (
+        cuda_wrapper.find_loaded_library("libcudart") == "/cuda/lib64/libcudart.so.13"
+    )
+
+
+if __name__ == "__main__":
+    raise SystemExit(pytest.main([__file__, "-v"]))