Fix segfault calling rmmGetInfo when uninitialized

When RMM is uninitialized (e.g. due to calling rmmFinalize()) a
call to rmmGetInfo can segfault in
rmm::detail::mr::device_memory_resource::get_mem_info() with an
invalid instance. This commit fixes the segfault by adding a check
to rmmGetInfo() which ensures that RMM is initialized before
proceeding to call get_mem_info().

Author: gmarkall

src/rmm.cpp

@@ -116,6 +116,8 @@ rmmError_t rmmGetAllocationOffset(ptrdiff_t *offset,
 // with the stream.
 rmmError_t rmmGetInfo(size_t *freeSize, size_t *totalSize, cudaStream_t stream)
 {
+  if (!rmmIsInitialized(nullptr))
+    return RMM_ERROR_NOT_INITIALIZED;
   try {
     std::pair<size_t,size_t> memInfo = rmm::mr::get_default_resource()->get_mem_info( stream);
     *freeSize = memInfo.first;

tests/memory_tests.cpp

@@ -86,6 +86,11 @@ TYPED_TEST(MemoryManagerUninitializedTest, UninitializedAllocateFree) {
     ASSERT_FAILURE(RMM_FREE(a, stream));
 }
 
+TYPED_TEST(MemoryManagerUninitializedTest, GetInfoUninitialized) {
+    size_t free, total;
+    ASSERT_FAILURE(rmmGetInfo(&free, &total, stream));
+}
+
 
 // Init / Finalize tests