diff --git a/nimble/host/test/src/ble_att_svr_test.c b/nimble/host/test/src/ble_att_svr_test.c
index d25118e4a..4a573fb5a 100644
--- a/nimble/host/test/src/ble_att_svr_test.c
+++ b/nimble/host/test/src/ble_att_svr_test.c
@@ -44,6 +44,8 @@ static uint16_t ble_att_svr_test_attr_n_len;
 static int
 ble_att_svr_test_misc_gap_cb(struct ble_gap_event *event, void *arg)
 {
+    int rc;
+
     switch (event->type) {
     case BLE_GAP_EVENT_NOTIFY_RX:
         ble_att_svr_test_n_conn_handle = event->notify_rx.conn_handle;
@@ -51,8 +53,10 @@ ble_att_svr_test_misc_gap_cb(struct ble_gap_event *event, void *arg)
         TEST_ASSERT_FATAL(OS_MBUF_PKTLEN(event->notify_rx.om) <=
                           sizeof ble_att_svr_test_attr_n);
         ble_att_svr_test_attr_n_len = OS_MBUF_PKTLEN(event->notify_rx.om);
-        os_mbuf_copydata(event->notify_rx.om, 0, ble_att_svr_test_attr_n_len,
-                         ble_att_svr_test_attr_n);
+        rc = os_mbuf_copydata(event->notify_rx.om, 0,
+                              ble_att_svr_test_attr_n_len,
+                              ble_att_svr_test_attr_n);
+        TEST_ASSERT_FATAL(rc == 0);
         break;
 
     default:
@@ -102,14 +106,17 @@ ble_att_svr_test_misc_attr_fn_r_1(uint16_t conn_handle, uint16_t attr_handle,
                                   uint8_t op, uint16_t offset,
                                   struct os_mbuf **om, void *arg)
 {
+    int rc;
+
     switch (op) {
     case BLE_ATT_ACCESS_OP_READ:
         if (offset > ble_att_svr_test_attr_r_1_len) {
             return BLE_ATT_ERR_INVALID_OFFSET;
         }
 
-        os_mbuf_append(*om, ble_att_svr_test_attr_r_1 + offset,
-                       ble_att_svr_test_attr_r_1_len - offset);
+        rc = os_mbuf_append(*om, ble_att_svr_test_attr_r_1 + offset,
+                            ble_att_svr_test_attr_r_1_len - offset);
+        TEST_ASSERT_FATAL(rc == 0);
         return 0;
 
     default:
@@ -122,6 +129,7 @@ ble_att_svr_test_misc_attr_fn_r_2(uint16_t conn_handle, uint16_t attr_handle,
                                   uint8_t op, uint16_t offset,
                                   struct os_mbuf **om, void *arg)
 {
+    int rc;
 
     switch (op) {
     case BLE_ATT_ACCESS_OP_READ:
@@ -129,8 +137,9 @@ ble_att_svr_test_misc_attr_fn_r_2(uint16_t conn_handle, uint16_t attr_handle,
             return BLE_ATT_ERR_INVALID_OFFSET;
         }
 
-        os_mbuf_append(*om, ble_att_svr_test_attr_r_2 + offset,
-                       ble_att_svr_test_attr_r_2_len - offset);
+        rc = os_mbuf_append(*om, ble_att_svr_test_attr_r_2 + offset,
+                            ble_att_svr_test_attr_r_2_len - offset);
+        TEST_ASSERT_FATAL(rc == 0);
         return 0;
 
     default:
@@ -143,7 +152,11 @@ ble_att_svr_test_misc_attr_fn_r_err(uint16_t conn_handle, uint16_t attr_handle,
                                     uint8_t op, uint16_t offset,
                                     struct os_mbuf **om, void *arg)
 {
-    os_mbuf_append(*om, (uint8_t[4]){1,2,3,4}, 4);
+    int rc;
+
+    rc = os_mbuf_append(*om, (uint8_t[4]){1,2,3,4}, 4);
+    TEST_ASSERT_FATAL(rc == 0);
+
     return BLE_ATT_ERR_UNLIKELY;
 }
 
@@ -286,19 +299,23 @@ ble_att_svr_test_misc_attr_fn_rw_1(uint16_t conn_handle, uint16_t attr_handle,
                                    uint8_t op, uint16_t offset,
                                    struct os_mbuf **om, void *arg)
 {
+    int rc;
+
     switch (op) {
     case BLE_ATT_ACCESS_OP_READ:
         if (offset > ble_att_svr_test_attr_w_1_len) {
             return BLE_ATT_ERR_INVALID_OFFSET;
         }
 
-        os_mbuf_append(*om, ble_att_svr_test_attr_w_1 + offset,
-                       ble_att_svr_test_attr_w_1_len - offset);
+        rc = os_mbuf_append(*om, ble_att_svr_test_attr_w_1 + offset,
+                            ble_att_svr_test_attr_w_1_len - offset);
+        TEST_ASSERT_FATAL(rc == 0);
         return 0;
 
     case BLE_ATT_ACCESS_OP_WRITE:
-        os_mbuf_copydata(*om, 0, OS_MBUF_PKTLEN(*om),
-                         ble_att_svr_test_attr_w_1);
+        rc = os_mbuf_copydata(*om, 0, OS_MBUF_PKTLEN(*om),
+                              ble_att_svr_test_attr_w_1);
+        TEST_ASSERT_FATAL(rc == 0);
         ble_att_svr_test_attr_w_1_len = OS_MBUF_PKTLEN(*om);
         return 0;
 
@@ -312,10 +329,13 @@ ble_att_svr_test_misc_attr_fn_w_1(uint16_t conn_handle, uint16_t attr_handle,
                                   uint8_t op, uint16_t offset,
                                   struct os_mbuf **om, void *arg)
 {
+    int rc;
+
     switch (op) {
     case BLE_ATT_ACCESS_OP_WRITE:
-        os_mbuf_copydata(*om, 0, OS_MBUF_PKTLEN(*om),
-                         ble_att_svr_test_attr_w_1);
+        rc = os_mbuf_copydata(*om, 0, OS_MBUF_PKTLEN(*om),
+                              ble_att_svr_test_attr_w_1);
+        TEST_ASSERT_FATAL(rc == 0);
         ble_att_svr_test_attr_w_1_len = OS_MBUF_PKTLEN(*om);
         return 0;
 
@@ -329,10 +349,13 @@ ble_att_svr_test_misc_attr_fn_w_2(uint16_t conn_handle, uint16_t attr_handle,
                                   uint8_t op, uint16_t offset,
                                   struct os_mbuf **om, void *arg)
 {
+    int rc;
+
     switch (op) {
     case BLE_ATT_ACCESS_OP_WRITE:
-        os_mbuf_copydata(*om, 0, OS_MBUF_PKTLEN(*om),
-                         ble_att_svr_test_attr_w_2);
+        rc = os_mbuf_copydata(*om, 0, OS_MBUF_PKTLEN(*om),
+                              ble_att_svr_test_attr_w_2);
+        TEST_ASSERT_FATAL(rc == 0);
         ble_att_svr_test_attr_w_2_len = OS_MBUF_PKTLEN(*om);
         return 0;
 
@@ -856,7 +879,8 @@ TEST_CASE(ble_att_svr_test_read)
     TEST_ASSERT(OS_MBUF_PKTLEN(om) == ble_att_svr_test_attr_r_1_len);
     TEST_ASSERT(os_mbuf_cmpf(om, 0, ble_att_svr_test_attr_r_1,
                                ble_att_svr_test_attr_r_1_len) == 0);
-    os_mbuf_free_chain(om);
+    rc = os_mbuf_free_chain(om);
+    TEST_ASSERT_FATAL(rc == 0);
 
     /* Ensure no response got sent. */
     ble_hs_test_util_tx_all();
@@ -2049,7 +2073,8 @@ TEST_CASE(ble_att_svr_test_oom)
     ble_hs_test_util_verify_tx_err_rsp(BLE_ATT_OP_INDICATE_REQ, 1,
                                        BLE_ATT_ERR_INSUFFICIENT_RES);
 
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
 }
 
 TEST_SUITE(ble_att_svr_suite)
diff --git a/nimble/host/test/src/ble_gatt_disc_c_test.c b/nimble/host/test/src/ble_gatt_disc_c_test.c
index 175224722..46ed1a556 100644
--- a/nimble/host/test/src/ble_gatt_disc_c_test.c
+++ b/nimble/host/test/src/ble_gatt_disc_c_test.c
@@ -589,7 +589,9 @@ TEST_CASE(ble_gatt_disc_c_test_oom_all)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify the procedure proceeds after mbufs become available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
+
     os_time_advance(ticks_until);
     ble_gattc_timer();
 
@@ -611,7 +613,9 @@ TEST_CASE(ble_gatt_disc_c_test_oom_all)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify that procedure completes when mbufs are available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
+
     os_time_advance(ticks_until);
     ble_gattc_timer();
 
@@ -678,7 +682,8 @@ TEST_CASE(ble_gatt_disc_c_test_oom_uuid)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify the procedure proceeds after mbufs become available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
 
@@ -700,7 +705,8 @@ TEST_CASE(ble_gatt_disc_c_test_oom_uuid)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify that procedure completes when mbufs are available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
 
diff --git a/nimble/host/test/src/ble_gatt_disc_d_test.c b/nimble/host/test/src/ble_gatt_disc_d_test.c
index 0b3dcc62e..b92c3bb9d 100644
--- a/nimble/host/test/src/ble_gatt_disc_d_test.c
+++ b/nimble/host/test/src/ble_gatt_disc_d_test.c
@@ -406,7 +406,8 @@ TEST_CASE(ble_gatt_disc_d_test_oom_all)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify the procedure proceeds after mbufs become available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
 
@@ -428,7 +429,8 @@ TEST_CASE(ble_gatt_disc_d_test_oom_all)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify the procedure succeeds after mbufs become available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
 
diff --git a/nimble/host/test/src/ble_gatt_disc_s_test.c b/nimble/host/test/src/ble_gatt_disc_s_test.c
index f4cff8666..d5dc7c0c7 100644
--- a/nimble/host/test/src/ble_gatt_disc_s_test.c
+++ b/nimble/host/test/src/ble_gatt_disc_s_test.c
@@ -442,7 +442,8 @@ TEST_CASE(ble_gatt_disc_s_test_oom_all)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify the procedure proceeds after mbufs become available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
 
@@ -461,7 +462,8 @@ TEST_CASE(ble_gatt_disc_s_test_oom_all)
     ticks_until = ble_gattc_timer();
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
 
@@ -521,7 +523,8 @@ TEST_CASE(ble_gatt_disc_s_test_oom_uuid)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify the procedure proceeds after mbufs become available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
     ble_hs_test_util_tx_all();
@@ -542,7 +545,8 @@ TEST_CASE(ble_gatt_disc_s_test_oom_uuid)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify that procedure completes when mbufs are available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
 
@@ -617,7 +621,8 @@ TEST_CASE(ble_gatt_disc_s_test_oom_timeout)
     TEST_ASSERT(ticks_until == BLE_HS_FOREVER);
     TEST_ASSERT(!ble_gattc_any_jobs());
 
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
 }
 
 TEST_SUITE(ble_gatt_disc_s_test_suite)
diff --git a/nimble/host/test/src/ble_gatt_find_s_test.c b/nimble/host/test/src/ble_gatt_find_s_test.c
index e6e0441e2..dbd997d90 100644
--- a/nimble/host/test/src/ble_gatt_find_s_test.c
+++ b/nimble/host/test/src/ble_gatt_find_s_test.c
@@ -395,7 +395,8 @@ TEST_CASE(ble_gatt_find_s_test_oom)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify the procedure succeeds after mbufs become available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
 
@@ -414,7 +415,8 @@ TEST_CASE(ble_gatt_find_s_test_oom)
     ble_gatt_find_s_test_misc_rx_read_type(1, incs + 1);
 
     /* Verify the procedure succeeds after mbufs become available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
 
diff --git a/nimble/host/test/src/ble_gatt_read_test.c b/nimble/host/test/src/ble_gatt_read_test.c
index 3cd784949..7d3ad3934 100644
--- a/nimble/host/test/src/ble_gatt_read_test.c
+++ b/nimble/host/test/src/ble_gatt_read_test.c
@@ -62,6 +62,7 @@ ble_gatt_read_test_cb(uint16_t conn_handle, const struct ble_gatt_error *error,
 {
     struct ble_gatt_read_test_attr *dst;
     int *stop_after;
+    int rc;
 
     stop_after = arg;
 
@@ -88,7 +89,8 @@ ble_gatt_read_test_cb(uint16_t conn_handle, const struct ble_gatt_error *error,
     dst->conn_handle = conn_handle;
     dst->handle = attr->handle;
     dst->value_len = OS_MBUF_PKTLEN(attr->om);
-    os_mbuf_copydata(attr->om, 0, OS_MBUF_PKTLEN(attr->om), dst->value);
+    rc = os_mbuf_copydata(attr->om, 0, OS_MBUF_PKTLEN(attr->om), dst->value);
+    TEST_ASSERT_FATAL(rc == 0);
 
     if (stop_after != NULL && *stop_after > 0) {
         (*stop_after)--;
@@ -110,6 +112,7 @@ ble_gatt_read_test_long_cb(uint16_t conn_handle,
 {
     struct ble_gatt_read_test_attr *dst;
     int *reads_left;
+    int rc;
 
     reads_left = arg;
 
@@ -140,8 +143,9 @@ ble_gatt_read_test_long_cb(uint16_t conn_handle,
         TEST_ASSERT(conn_handle == dst->conn_handle);
         TEST_ASSERT(attr->handle == dst->handle);
     }
-    os_mbuf_copydata(attr->om, 0, OS_MBUF_PKTLEN(attr->om),
-                     dst->value + dst->value_len);
+    rc = os_mbuf_copydata(attr->om, 0, OS_MBUF_PKTLEN(attr->om),
+                          dst->value + dst->value_len);
+    TEST_ASSERT_FATAL(rc == 0);
     dst->value_len += OS_MBUF_PKTLEN(attr->om);
 
     if (reads_left != NULL && *reads_left > 0) {
@@ -859,7 +863,8 @@ TEST_CASE(ble_gatt_read_test_long_oom)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify the procedure proceeds after mbufs become available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
     ble_hs_test_util_tx_all();
@@ -883,7 +888,8 @@ TEST_CASE(ble_gatt_read_test_long_oom)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify that procedure completes when mbufs are available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
 
diff --git a/nimble/host/test/src/ble_gatt_write_test.c b/nimble/host/test/src/ble_gatt_write_test.c
index da6f23ac4..66ff3db43 100644
--- a/nimble/host/test/src/ble_gatt_write_test.c
+++ b/nimble/host/test/src/ble_gatt_write_test.c
@@ -665,7 +665,8 @@ TEST_CASE(ble_gatt_write_test_long_oom)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify the procedure proceeds after mbufs become available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
     ble_hs_test_util_tx_all();
@@ -692,7 +693,8 @@ TEST_CASE(ble_gatt_write_test_long_oom)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify that procedure completes when mbufs are available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
 
@@ -763,7 +765,8 @@ TEST_CASE(ble_gatt_write_test_reliable_oom)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify the procedure proceeds after mbufs become available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
     ble_hs_test_util_tx_all();
@@ -790,7 +793,8 @@ TEST_CASE(ble_gatt_write_test_reliable_oom)
     TEST_ASSERT(ticks_until == BLE_GATT_RESUME_RATE_TICKS);
 
     /* Verify that procedure completes when mbufs are available. */
-    os_mbuf_free_chain(oms);
+    rc = os_mbuf_free_chain(oms);
+    TEST_ASSERT_FATAL(rc == 0);
     os_time_advance(ticks_until);
     ble_gattc_timer();
 
diff --git a/nimble/host/test/src/ble_hs_test_util.c b/nimble/host/test/src/ble_hs_test_util.c
index 896f0ab5f..d6d763456 100644
--- a/nimble/host/test/src/ble_hs_test_util.c
+++ b/nimble/host/test/src/ble_hs_test_util.c
@@ -110,7 +110,8 @@ ble_hs_test_util_prev_tx_dequeue(void)
     uint8_t pb;
     int rc;
 
-    os_mbuf_free_chain(ble_hs_test_util_prev_tx_cur);
+    rc = os_mbuf_free_chain(ble_hs_test_util_prev_tx_cur);
+    TEST_ASSERT_FATAL(rc == 0);
 
     om = ble_hs_test_util_prev_tx_dequeue_once(&hci_hdr);
     if (om != NULL) {
@@ -974,7 +975,8 @@ ble_hs_test_util_l2cap_rx(uint16_t conn_handle,
     if (conn != NULL) {
         rc = ble_l2cap_rx(conn, hci_hdr, om, &rx_cb, &reject_cid);
     } else {
-        os_mbuf_free_chain(om);
+        rc = os_mbuf_free_chain(om);
+        TEST_ASSERT_FATAL(rc == 0);
     }
 
     ble_hs_unlock();
@@ -2084,7 +2086,8 @@ ble_hs_test_util_read_local_flat(uint16_t attr_handle, uint16_t max_len,
 
     *out_len = OS_MBUF_PKTLEN(om);
 
-    os_mbuf_free_chain(om);
+    rc = os_mbuf_free_chain(om);
+    TEST_ASSERT_FATAL(rc == 0);
     return 0;
 }
 
@@ -2163,6 +2166,7 @@ ble_hs_test_util_mbuf_alloc_all_but(int count)
 {
     struct os_mbuf *prev;
     struct os_mbuf *om;
+    int rc;
     int i;
 
     /* Allocate all available mbufs and put them in a single chain. */
@@ -2184,7 +2188,8 @@ ble_hs_test_util_mbuf_alloc_all_but(int count)
     for (i = 0; i < count; i++) {
         TEST_ASSERT_FATAL(prev != NULL);
         om = SLIST_NEXT(prev, om_next);
-        os_mbuf_free(prev);
+        rc = os_mbuf_free(prev);
+        TEST_ASSERT_FATAL(rc == 0);
 
         prev = om;
     }
diff --git a/nimble/host/test/src/ble_l2cap_test.c b/nimble/host/test/src/ble_l2cap_test.c
index ece2e37a9..85bf22c17 100644
--- a/nimble/host/test/src/ble_l2cap_test.c
+++ b/nimble/host/test/src/ble_l2cap_test.c
@@ -750,7 +750,8 @@ ble_l2cap_test_coc_connect(struct test_data *t)
     TEST_ASSERT_FATAL(rc == ev->early_error);
 
     if (rc != 0) {
-        os_mbuf_free_chain(sdu_rx);
+        rc = os_mbuf_free_chain(sdu_rx);
+        TEST_ASSERT_FATAL(rc == 0);
         return;
     }
 
@@ -953,8 +954,11 @@ ble_l2cap_test_coc_send_data(struct test_data *t)
     TEST_ASSERT(rc == ev->early_error);
 
     if (rc) {
-        os_mbuf_free(sdu);
-        os_mbuf_free(sdu_copy);
+        rc = os_mbuf_free(sdu);
+        TEST_ASSERT_FATAL(rc == 0);
+
+        rc = os_mbuf_free(sdu_copy);
+        TEST_ASSERT_FATAL(rc == 0);
         return;
     }
 
@@ -965,7 +969,8 @@ ble_l2cap_test_coc_send_data(struct test_data *t)
 
     ble_hs_test_util_verify_tx_l2cap(sdu);
 
-    os_mbuf_free_chain(sdu_copy);
+    rc = os_mbuf_free_chain(sdu_copy);
+    TEST_ASSERT_FATAL(rc == 0);
 }
 
 static void