diff --git a/nbdkit.spec b/nbdkit.spec
index a8592dd..8c51afb 100644
--- a/nbdkit.spec
+++ b/nbdkit.spec
@@ -817,22 +817,40 @@ rm -f $RPM_BUILD_ROOT%{_mandir}/man1/nbdkit-S3-plugin.1*
 
 %check
 %ifnarch %{broken_test_arches}
+function skip_test ()
+{
+    for f in "$@"; do
+        rm -f "$f"
+        echo 'exit 77' > "$f"
+        chmod +x "$f"
+    done
+}
+
 # Workaround for broken libvirt (RHBZ#1138604).
 mkdir -p $HOME/.cache/libvirt
 
 # tests/test-captive.sh is racy especially on s390x.  We need to
 # rethink this test upstream.
-truncate -s 0 tests/test-captive.sh
+skip_test tests/test-captive.sh
 
 %ifarch s390x
 # Temporarily kill tests/test-cache-max-size.sh since it fails
 # sometimes on s390x for unclear reasons.
-truncate -s 0 tests/test-cache-max-size.sh
+skip_test tests/test-cache-max-size.sh
 %endif
 
 # Temporarily kill test-nbd-tls.sh and test-nbd-tls-psk.sh
 # https://www.redhat.com/archives/libguestfs/2020-March/msg00191.html
-truncate -s 0 tests/test-nbd-tls.sh tests/test-nbd-tls-psk.sh
+skip_test tests/test-nbd-tls.sh tests/test-nbd-tls-psk.sh
+
+# This test fails on RHEL 9 & aarch64 with the error:
+# nbdkit: error: allocator=malloc: mlock: Cannot allocate memory
+# It could be the mlock limit on the builder is too low.
+%if 0%{?rhel}
+%ifarch aarch64
+skip_test tests/test-memory-allocator-malloc-mlock.sh
+%endif
+%endif
 
 # Make sure we can see the debug messages (RHBZ#1230160).
 export LIBGUESTFS_DEBUG=1