diff --git a/tests/refcount/closures.c b/tests/refcount/closures.c
index 25b0a2779..188406786 100644
--- a/tests/refcount/closures.c
+++ b/tests/refcount/closures.c
@@ -259,7 +259,19 @@ main (int    argc,
   thread1 = g_thread_create (thread1_main, closure, TRUE, NULL);
   thread2 = g_thread_create (thread2_main, closure, TRUE, NULL);
 
+  /* The 16-bit compare-and-swap operations currently used for closure
+   * refcounts are really slow on some ARM CPUs, notably Cortex-A57.
+   * Reduce the number of iterations so that the test completes in a
+   * finite time, but don't reduce it so much that the main thread
+   * starves the other threads and causes a test failure.
+   *
+   * https://gitlab.gnome.org/GNOME/glib/issues/1316
+   * aka https://bugs.debian.org/880883 */
+#if defined(__aarch64__) || defined(__arm__)
+  for (i = 0; i < 100000; i++)
+#else
   for (i = 0; i < 1000000; i++)
+#endif
     {
       static guint count = 0;
       test_emissions (object);
diff --git a/tests/refcount/meson.build b/tests/refcount/meson.build
index 68c23cc41..22b9655d7 100644
--- a/tests/refcount/meson.build
+++ b/tests/refcount/meson.build
@@ -54,6 +54,13 @@ foreach test_name, extra_args : refcount_tests
 
   suite = ['refcount'] + extra_args.get('suite', [])
   timeout = suite.contains('slow') ? test_timeout_slow : test_timeout
+
+  # https://gitlab.gnome.org/GNOME/glib/issues/1316
+  # aka https://bugs.debian.org/880883
+  if test_name == 'closures' and ['arm', 'aarch64'].contains(host_cpu_family)
+    timeout = timeout * 10
+  endif
+
   # FIXME? TESTS_ENVIRONMENT = LIBCHARSET_ALIAS_DIR=$(top_builddir)/glib/libcharset
   test(test_name, exe, env : test_env, timeout : timeout, suite : suite)
 endforeach