diff --git a/cmake.spec b/cmake.spec
index ced3632..f17b01f 100644
--- a/cmake.spec
+++ b/cmake.spec
@@ -417,6 +417,10 @@ pushd %{_vpath_builddir}
 # CTestTestUpload require internet access
 # CPackComponentsForAll-RPM-IgnoreGroup failing wih rpm 4.15 - https://gitlab.kitware.com/cmake/cmake/issues/19983
 NO_TEST="CTestTestUpload|CPackComponentsForAll-RPM-IgnoreGroup"
+# kwsys.testProcess-{4,5} are flaky on s390x.
+%ifarch s390x
+NO_TEST="$NO_TEST|kwsys.testProcess-4|kwsys.testProcess-5"
+%endif
 bin/ctest%{?name_suffix} %{?_smp_mflags} -V -E "$NO_TEST" --output-on-failure
 # Keep an eye on failing tests
 bin/ctest%{?name_suffix} %{?_smp_mflags} -V -R "$NO_TEST" --output-on-failure || :