diff --git a/openbsc/tests/sgsn/sgsn_test.c b/openbsc/tests/sgsn/sgsn_test.c
index 8181061..d419f0a 100644
--- a/openbsc/tests/sgsn/sgsn_test.c
+++ b/openbsc/tests/sgsn/sgsn_test.c
@@ -546,6 +546,97 @@
 	update_subscriber_data_cb = __real_sgsn_update_subscriber_data;
 }
 
+int my_gprs_gsup_client_send_dummy(struct gprs_gsup_client *gsupc, struct msgb *msg)
+{
+	msgb_free(msg);
+	return 0;
+};
+
+
+static void test_subscriber_blocking(void)
+{
+	struct gsm_subscriber *s1;
+	const char *imsi1 = "1234567890";
+	struct sgsn_mm_ctx *ctx;
+	struct gprs_ra_id raid = { 0, };
+	uint32_t local_tlli = 0xffeeddcc;
+	struct gprs_llc_llme *llme;
+	int rc;
+
+	printf("Testing subcriber procedure blocking\n");
+
+	gprs_gsup_client_send_cb = my_gprs_gsup_client_send_dummy;
+	sgsn->gsup_client = talloc_zero(tall_bsc_ctx, struct gprs_gsup_client);
+
+	/* Check for emptiness */
+	OSMO_ASSERT(gprs_subscr_get_by_imsi(imsi1) == NULL);
+
+	/* Create a context */
+	OSMO_ASSERT(count(gprs_llme_list()) == 0);
+	ctx = alloc_mm_ctx(local_tlli, &raid);
+	llme = ctx->llme;
+	strncpy(ctx->imsi, imsi1, sizeof(ctx->imsi) - 1);
+
+	/* Allocate and attach a subscriber */
+	s1 = gprs_subscr_get_or_create_by_mmctx(ctx);
+	assert_subscr(s1, imsi1);
+
+	/* Start SendAuthInfoRequest procedure */
+	rc = gprs_subscr_query_auth_info(s1);
+	/* Not blocking */
+	OSMO_ASSERT(rc == 0);
+
+	/* Start UpdateLocation procedure */
+	rc = gprs_subscr_location_update(s1);
+	/* Blocking */
+	OSMO_ASSERT(rc == 0);
+
+	/* Start PurgeMS procedure */
+	rc = gprs_subscr_purge(s1);
+	/* Not blocking */
+	OSMO_ASSERT(rc == 0);
+	OSMO_ASSERT(s1->sgsn_data->blocked_by == SGSN_SUBSCR_PROC_PURGE);
+
+	/* Start PurgeMS procedure (retry) */
+	rc = gprs_subscr_purge(s1);
+	/* Not blocking */
+	OSMO_ASSERT(rc == 0);
+
+	/* Start SendAuthInfoRequest procedure */
+	rc = gprs_subscr_query_auth_info(s1);
+	/* Blocking */
+	OSMO_ASSERT(rc == -EAGAIN);
+
+	/* Start UpdateLocation procedure */
+	rc = gprs_subscr_location_update(s1);
+	/* Blocking */
+	OSMO_ASSERT(rc == -EAGAIN);
+
+	/* Unblock manually (normally done by the caller of gprs_subscr_purge) */
+	s1->sgsn_data->blocked_by = SGSN_SUBSCR_PROC_NONE;
+
+	/* Start SendAuthInfoRequest procedure */
+	rc = gprs_subscr_query_auth_info(s1);
+	/* Not blocking */
+	OSMO_ASSERT(rc == 0);
+
+	/* Start UpdateLocation procedure */
+	rc = gprs_subscr_location_update(s1);
+	/* Blocking */
+	OSMO_ASSERT(rc == 0);
+
+	subscr_put(s1);
+	sgsn_mm_ctx_free(ctx);
+	gprs_llgmm_assign(llme, local_tlli, 0xffffffff, GPRS_ALGO_GEA0, NULL);
+
+	assert_no_subscrs();
+
+	gprs_gsup_client_send_cb = __real_gprs_gsup_client_send;
+	talloc_free(sgsn->gsup_client);
+	sgsn->gsup_client = NULL;
+}
+
+
 /*
  * Test that a GMM Detach will remove the MMCTX and the
  * associated LLME.
@@ -1710,6 +1801,7 @@
 	test_subscriber();
 	test_auth_triplets();
 	test_subscriber_gsup();
+	test_subscriber_blocking();
 	test_gmm_detach();
 	test_gmm_detach_power_off();
 	test_gmm_detach_no_mmctx();