Fix segfault in get_capture_info_v2

Author: nimlgen

src/cpp/cuda.hpp

@@ -1679,9 +1679,9 @@ namespace pycuda
   {
     CUgraph _capturing_graph;
     CUstreamCaptureStatus _capture_status;
-    const CUgraphNode *_deps;
-    size_t _dep_count;
-    uint64_t _id_out;
+    const CUgraphNode *_deps = nullptr;
+    size_t _dep_count = 0;
+    uint64_t _id_out = 0;
     CUDAPP_CALL_GUARDED(cuStreamGetCaptureInfo_v2, (m_stream, &_capture_status, &_id_out, &_capturing_graph, &_deps, &_dep_count));
     py::list list_root_nodes = array_of_nodes_to_list(_deps, _dep_count);
     graph *node = new graph(_capturing_graph);

test/test_graph.py

@@ -96,13 +96,15 @@ def test_many_dynamic_params(self):
         func_times = mod.get_function("times")
 
         stream_1 = drv.Stream()
+        _ , _, _, _ = stream_1.get_capture_info_v2()
 
         import numpy
         a = numpy.zeros((4, 4)).astype(numpy.float32)
         a_gpu = drv.mem_alloc_like(a)
         b = numpy.zeros((4, 4)).astype(numpy.float32)
         b_gpu = drv.mem_alloc_like(b)
         result = numpy.zeros_like(b)
+        _ , _, _, _ = stream_1.get_capture_info_v2()
         stream_1.begin_capture()
         stat , _, x_graph, deps = stream_1.get_capture_info_v2()
         assert stat == drv.capture_status.ACTIVE, "Capture should be active"