diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index e5d81bcb174f42123648ba39353b8ca7ed286bac..d658c057a5d965d98a8136fe7bc876ad8658883e 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,13 +1,13 @@
-Python 2.7 Intel CPU:
+Python 2.7 Nvidia K40:
   script:
   - export PY_EXE=python2.7
-  - export PYOPENCL_TEST=intel
+  - export PYOPENCL_TEST=nvi:k40
   - export EXTRA_INSTALL="numpy mako"
   - curl -L -O -k https://gitlab.tiker.net/inducer/ci-support/raw/master/build-and-test-py-project.sh
   - ". ./build-and-test-py-project.sh"
   tags:
   - python2.7
-  - intel-cl-cpu
+  - nvidia-k40
   except:
   - tags
 
diff --git a/meshmode/mesh/processing.py b/meshmode/mesh/processing.py
index 1c961e4b0dd2cfee0940df6192044a7bf30aaf70..d420c08d0fc88867e3a67488abd959486946eca3 100644
--- a/meshmode/mesh/processing.py
+++ b/meshmode/mesh/processing.py
@@ -409,6 +409,10 @@ def merge_disjoint_meshes(meshes, skip_tests=False, single_group=False):
             for mesh in meshes
             for group in mesh.groups])
 
+        if not nodes.flags.c_contiguous:
+            # hstack stopped producing C-contiguous arrays in numpy 1.14
+            nodes = nodes.copy(order="C")
+
         new_groups = [
                 grp_cls(order, vertex_indices, nodes, unit_nodes=unit_nodes)]