Fix a pointer comparison bug in hl_dso_loader.cc

paddle/cuda/src/hl_dso_loader.cc

@@ -19,7 +19,7 @@ limitations under the License. */
 
 P_DEFINE_string(cudnn_dir, "",
                 "Specify path for loading libcudnn.so. For instance, "
-                "/usr/local/cudnn/lib64. If empty [default], dlopen "
+                "/usr/local/cudnn/lib. If empty [default], dlopen "
                 "will search cudnn from LD_LIBRARY_PATH");
 
 P_DEFINE_string(cuda_dir, "",
@@ -33,7 +33,6 @@ static inline std::string join(const std::string& part1,
                                const std::string& part2) {
     // directory separator
     const char sep = '/';
-
     if (!part2.empty() && part2.front() == sep) {
         return part2;
     }
@@ -88,7 +87,7 @@ static inline void GetDsoHandleFromSearchPath(
         dlPath = join(search_root, dso_name);
         *dso_handle = dlopen(dlPath.c_str(), dynload_flags);
         // if not found, search from default path
-        if (nullptr == dso_handle) {
+        if (nullptr == *dso_handle) {
             LOG(WARNING) << "Failed to find cuda library: " << dlPath;
             dlPath = dso_name;
             GetDsoHandleFromDefaultPath(dlPath, dso_handle, dynload_flags);