diff --git a/lib/isc/netmgr/netmgr.c b/lib/isc/netmgr/netmgr.c
index 481cc61586..ecdb26340d 100644
--- a/lib/isc/netmgr/netmgr.c
+++ b/lib/isc/netmgr/netmgr.c
@@ -295,20 +295,21 @@ isc__netmgr_create(isc_mem_t *mctx, uint32_t workers, isc_nm_t **netmgrp) {
 
 	mgr->workers = isc_mem_get(mctx, workers * sizeof(isc__networker_t));
 	for (size_t i = 0; i < workers; i++) {
-		int r;
 		isc__networker_t *worker = &mgr->workers[i];
+		int r;
+
 		*worker = (isc__networker_t){
 			.mgr = mgr,
 			.id = i,
 		};
 
 		r = uv_loop_init(&worker->loop);
-		RUNTIME_CHECK(r == 0);
+		UV_RUNTIME_CHECK(uv_loop_init, r);
 
 		worker->loop.data = &mgr->workers[i];
 
 		r = uv_async_init(&worker->loop, &worker->async, async_cb);
-		RUNTIME_CHECK(r == 0);
+		UV_RUNTIME_CHECK(uv_async_init, r);
 
 		isc_mutex_init(&worker->lock);
 		isc_condition_init(&worker->cond_prio);
@@ -384,7 +385,7 @@ nm_destroy(isc_nm_t **mgr0) {
 		isc_mutex_destroy(&worker->lock);
 
 		r = uv_loop_close(&worker->loop);
-		INSIST(r == 0);
+		UV_RUNTIME_CHECK(uv_loop_close, r);
 
 		for (size_t type = 0; type < NETIEVENT_MAX; type++) {
 			isc_queue_destroy(worker->ievents[type]);
@@ -2098,11 +2099,11 @@ isc__nmsocket_readtimeout_cb(uv_timer_t *timer) {
 
 void
 isc__nmsocket_timer_restart(isc_nmsocket_t *sock) {
-	int r = 0;
-
 	REQUIRE(VALID_NMSOCK(sock));
 
 	if (atomic_load(&sock->connecting)) {
+		int r;
+
 		if (sock->connect_timeout == 0) {
 			return;
 		}
@@ -2110,17 +2111,19 @@ isc__nmsocket_timer_restart(isc_nmsocket_t *sock) {
 		r = uv_timer_start(&sock->timer,
 				   isc__nmsocket_connecttimeout_cb,
 				   sock->connect_timeout + 10, 0);
+		UV_RUNTIME_CHECK(uv_timer_start, r);
 
 	} else {
+		int r;
+
 		if (sock->read_timeout == 0) {
 			return;
 		}
 
 		r = uv_timer_start(&sock->timer, isc__nmsocket_readtimeout_cb,
 				   sock->read_timeout, 0);
+		UV_RUNTIME_CHECK(uv_timer_start, r);
 	}
-
-	RUNTIME_CHECK(r == 0);
 }
 
 bool
@@ -2143,12 +2146,14 @@ isc__nmsocket_timer_start(isc_nmsocket_t *sock) {
 
 void
 isc__nmsocket_timer_stop(isc_nmsocket_t *sock) {
+	int r;
+
 	REQUIRE(VALID_NMSOCK(sock));
 
 	/* uv_timer_stop() is idempotent, no need to check if running */
 
-	int r = uv_timer_stop(&sock->timer);
-	RUNTIME_CHECK(r == 0);
+	r = uv_timer_stop(&sock->timer);
+	UV_RUNTIME_CHECK(uv_timer_stop, r);
 }
 
 isc__nm_uvreq_t *
@@ -2232,24 +2237,27 @@ isc__nm_start_reading(isc_nmsocket_t *sock) {
 	case isc_nm_udpsocket:
 		r = uv_udp_recv_start(&sock->uv_handle.udp, isc__nm_alloc_cb,
 				      isc__nm_udp_read_cb);
+		UV_RUNTIME_CHECK(uv_udp_recv_start, r);
 		break;
 	case isc_nm_tcpsocket:
 		r = uv_read_start(&sock->uv_handle.stream, isc__nm_alloc_cb,
 				  isc__nm_tcp_read_cb);
+		UV_RUNTIME_CHECK(uv_read_start, r);
 		break;
 	case isc_nm_tcpdnssocket:
 		r = uv_read_start(&sock->uv_handle.stream, isc__nm_alloc_cb,
 				  isc__nm_tcpdns_read_cb);
+		UV_RUNTIME_CHECK(uv_read_start, r);
 		break;
 	case isc_nm_tlsdnssocket:
 		r = uv_read_start(&sock->uv_handle.stream, isc__nm_alloc_cb,
 				  isc__nm_tlsdns_read_cb);
+		UV_RUNTIME_CHECK(uv_read_start, r);
 		break;
 	default:
 		INSIST(0);
 		ISC_UNREACHABLE();
 	}
-	RUNTIME_CHECK(r == 0);
 	atomic_store(&sock->reading, true);
 }
 
@@ -2264,17 +2272,18 @@ isc__nm_stop_reading(isc_nmsocket_t *sock) {
 	switch (sock->type) {
 	case isc_nm_udpsocket:
 		r = uv_udp_recv_stop(&sock->uv_handle.udp);
+		UV_RUNTIME_CHECK(uv_udp_recv_stop, r);
 		break;
 	case isc_nm_tcpsocket:
 	case isc_nm_tcpdnssocket:
 	case isc_nm_tlsdnssocket:
 		r = uv_read_stop(&sock->uv_handle.stream);
+		UV_RUNTIME_CHECK(uv_read_stop, r);
 		break;
 	default:
 		INSIST(0);
 		ISC_UNREACHABLE();
 	}
-	RUNTIME_CHECK(r == 0);
 	atomic_store(&sock->reading, false);
 }
 
@@ -3322,12 +3331,12 @@ isc__nm_set_network_buffers(isc_nm_t *nm, uv_handle_t *handle) {
 
 	if (recv_buffer_size > 0) {
 		int r = uv_recv_buffer_size(handle, &recv_buffer_size);
-		INSIST(r == 0);
+		UV_RUNTIME_CHECK(uv_recv_buffer_size, r);
 	}
 
 	if (send_buffer_size > 0) {
 		int r = uv_send_buffer_size(handle, &send_buffer_size);
-		INSIST(r == 0);
+		UV_RUNTIME_CHECK(uv_send_buffer_size, r);
 	}
 }
 
@@ -3395,7 +3404,7 @@ isc_nm_work_offload(isc_nm_t *netmgr, isc_nm_workcb_t work_cb,
 
 	r = uv_queue_work(&worker->loop, &work->req, isc__nm_work_cb,
 			  isc__nm_after_work_cb);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_queue_work, r);
 }
 
 void
diff --git a/lib/isc/netmgr/tcp.c b/lib/isc/netmgr/tcp.c
index b0034b9cbf..45339244c7 100644
--- a/lib/isc/netmgr/tcp.c
+++ b/lib/isc/netmgr/tcp.c
@@ -137,11 +137,11 @@ tcp_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
 	RUNTIME_CHECK(result == ISC_R_SUCCESS);
 
 	r = uv_tcp_init(&worker->loop, &sock->uv_handle.tcp);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
 	uv_handle_set_data(&sock->uv_handle.handle, sock);
 
 	r = uv_timer_init(&worker->loop, &sock->timer);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
 
 	r = uv_tcp_open(&sock->uv_handle.tcp, sock->fd);
 	if (r != 0) {
@@ -521,14 +521,14 @@ isc__nm_async_tcplisten(isc__networker_t *worker, isc__netievent_t *ev0) {
 	/* TODO: set min mss */
 
 	r = uv_tcp_init(&worker->loop, &sock->uv_handle.tcp);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
 
 	uv_handle_set_data(&sock->uv_handle.handle, sock);
 	/* This keeps the socket alive after everything else is gone */
 	isc__nmsocket_attach(sock, &(isc_nmsocket_t *){ NULL });
 
 	r = uv_timer_init(&worker->loop, &sock->timer);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
 
 	uv_handle_set_data((uv_handle_t *)&sock->timer, sock);
 
@@ -971,11 +971,11 @@ accept_connection(isc_nmsocket_t *ssock, isc_quota_t *quota) {
 	worker = &csock->mgr->workers[isc_nm_tid()];
 
 	r = uv_tcp_init(&worker->loop, &csock->uv_handle.tcp);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
 	uv_handle_set_data(&csock->uv_handle.handle, csock);
 
 	r = uv_timer_init(&worker->loop, &csock->timer);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&csock->timer, csock);
 
 	r = uv_accept(&ssock->uv_handle.stream, &csock->uv_handle.stream);
diff --git a/lib/isc/netmgr/tcpdns.c b/lib/isc/netmgr/tcpdns.c
index 21d1ab5bc6..ce31e30c86 100644
--- a/lib/isc/netmgr/tcpdns.c
+++ b/lib/isc/netmgr/tcpdns.c
@@ -102,11 +102,11 @@ tcpdns_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
 	atomic_store(&sock->connecting, true);
 
 	r = uv_tcp_init(&worker->loop, &sock->uv_handle.tcp);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
 	uv_handle_set_data(&sock->uv_handle.handle, sock);
 
 	r = uv_timer_init(&worker->loop, &sock->timer);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
 
 	if (isc__nm_closing(sock)) {
 		result = ISC_R_SHUTTINGDOWN;
@@ -492,13 +492,13 @@ isc__nm_async_tcpdnslisten(isc__networker_t *worker, isc__netievent_t *ev0) {
 	/* TODO: set min mss */
 
 	r = uv_tcp_init(&worker->loop, &sock->uv_handle.tcp);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
 	uv_handle_set_data(&sock->uv_handle.handle, sock);
 	/* This keeps the socket alive after everything else is gone */
 	isc__nmsocket_attach(sock, &(isc_nmsocket_t *){ NULL });
 
 	r = uv_timer_init(&worker->loop, &sock->timer);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->timer, sock);
 
 	LOCK(&sock->parent->lock);
@@ -963,11 +963,11 @@ accept_connection(isc_nmsocket_t *ssock, isc_quota_t *quota) {
 	worker = &csock->mgr->workers[csock->tid];
 
 	r = uv_tcp_init(&worker->loop, &csock->uv_handle.tcp);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
 	uv_handle_set_data(&csock->uv_handle.handle, csock);
 
 	r = uv_timer_init(&worker->loop, &csock->timer);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&csock->timer, csock);
 
 	r = uv_accept(&ssock->uv_handle.stream, &csock->uv_handle.stream);
@@ -1162,7 +1162,7 @@ isc__nm_async_tcpdnssend(isc__networker_t *worker, isc__netievent_t *ev0) {
 		bufs[0].base = uvreq->uvbuf.base + (r - 2);
 		bufs[0].len = uvreq->uvbuf.len - (r - 2);
 	} else if (r == UV_ENOSYS || r == UV_EAGAIN) {
-		/* uv_try_write not support, send asynchronously */
+		/* uv_try_write not supported, send asynchronously */
 	} else {
 		/* error sending data */
 		result = isc__nm_uverr2result(r);
@@ -1177,12 +1177,9 @@ isc__nm_async_tcpdnssend(isc__networker_t *worker, isc__netievent_t *ev0) {
 	}
 
 	return;
-
 fail:
-	if (result != ISC_R_SUCCESS) {
-		isc__nm_incstats(sock, STATID_SENDFAIL);
-		isc__nm_failed_send_cb(sock, uvreq, result);
-	}
+	isc__nm_incstats(sock, STATID_SENDFAIL);
+	isc__nm_failed_send_cb(sock, uvreq, result);
 }
 
 static void
diff --git a/lib/isc/netmgr/tlsdns.c b/lib/isc/netmgr/tlsdns.c
index d56c82857a..bd564bac25 100644
--- a/lib/isc/netmgr/tlsdns.c
+++ b/lib/isc/netmgr/tlsdns.c
@@ -118,11 +118,11 @@ tlsdns_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
 	RUNTIME_CHECK(result == ISC_R_SUCCESS);
 
 	r = uv_tcp_init(&worker->loop, &sock->uv_handle.tcp);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
 	uv_handle_set_data(&sock->uv_handle.handle, sock);
 
 	r = uv_timer_init(&worker->loop, &sock->timer);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->timer, sock);
 
 	if (isc__nm_closing(sock)) {
@@ -564,13 +564,13 @@ isc__nm_async_tlsdnslisten(isc__networker_t *worker, isc__netievent_t *ev0) {
 	/* TODO: set min mss */
 
 	r = uv_tcp_init(&worker->loop, &sock->uv_handle.tcp);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
 	uv_handle_set_data(&sock->uv_handle.handle, sock);
 	/* This keeps the socket alive after everything else is gone */
 	isc__nmsocket_attach(sock, &(isc_nmsocket_t *){ NULL });
 
 	r = uv_timer_init(&worker->loop, &sock->timer);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->timer, sock);
 
 	LOCK(&sock->parent->lock);
@@ -1188,7 +1188,7 @@ tls_cycle_output(isc_nmsocket_t *sock) {
 		isc__nm_uvreq_t *req = NULL;
 		size_t bytes;
 		int rv;
-		int err;
+		int r;
 
 		if (sock->tls.senddata.base != NULL ||
 		    sock->tls.senddata.length > 0) {
@@ -1212,34 +1212,38 @@ tls_cycle_output(isc_nmsocket_t *sock) {
 		RUNTIME_CHECK(rv == 1);
 		INSIST((size_t)pending == bytes);
 
-		err = uv_try_write(&sock->uv_handle.stream, &req->uvbuf, 1);
+		r = uv_try_write(&sock->uv_handle.stream, &req->uvbuf, 1);
 
-		if (err == pending) {
+		if (r == pending) {
 			/* Wrote everything, restart */
 			isc__nm_uvreq_put(&req, sock);
 			free_senddata(sock);
 			continue;
 		}
 
-		if (err > 0) {
+		if (r > 0) {
 			/* Partial write, send rest asynchronously */
-			memmove(req->uvbuf.base, req->uvbuf.base + err,
-				req->uvbuf.len - err);
-			req->uvbuf.len = req->uvbuf.len - err;
-		} else if (err == UV_ENOSYS || err == UV_EAGAIN) {
+			memmove(req->uvbuf.base, req->uvbuf.base + r,
+				req->uvbuf.len - r);
+			req->uvbuf.len = req->uvbuf.len - r;
+		} else if (r == UV_ENOSYS || r == UV_EAGAIN) {
 			/* uv_try_write is not supported, send
 			 * asynchronously */
 		} else {
-			result = isc__nm_uverr2result(err);
+			result = isc__nm_uverr2result(r);
 			isc__nm_uvreq_put(&req, sock);
 			free_senddata(sock);
 			break;
 		}
 
-		err = uv_write(&req->uv_req.write, &sock->uv_handle.stream,
-			       &req->uvbuf, 1, tls_write_cb);
-
-		INSIST(err == 0);
+		r = uv_write(&req->uv_req.write, &sock->uv_handle.stream,
+			     &req->uvbuf, 1, tls_write_cb);
+		if (r < 0) {
+			result = isc__nm_uverr2result(r);
+			isc__nm_uvreq_put(&req, sock);
+			free_senddata(sock);
+			break;
+		}
 
 		break;
 	}
@@ -1469,11 +1473,11 @@ accept_connection(isc_nmsocket_t *ssock, isc_quota_t *quota) {
 	worker = &csock->mgr->workers[csock->tid];
 
 	r = uv_tcp_init(&worker->loop, &csock->uv_handle.tcp);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
 	uv_handle_set_data(&csock->uv_handle.handle, csock);
 
 	r = uv_timer_init(&worker->loop, &csock->timer);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&csock->timer, csock);
 
 	r = uv_accept(&ssock->uv_handle.stream, &csock->uv_handle.stream);
diff --git a/lib/isc/netmgr/udp.c b/lib/isc/netmgr/udp.c
index 0b7f01037f..3573836785 100644
--- a/lib/isc/netmgr/udp.c
+++ b/lib/isc/netmgr/udp.c
@@ -262,11 +262,11 @@ route_connect_direct(isc_nmsocket_t *sock) {
 	atomic_store(&sock->connecting, true);
 
 	r = uv_udp_init(&worker->loop, &sock->uv_handle.udp);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_udp_init, r);
 	uv_handle_set_data(&sock->uv_handle.handle, sock);
 
 	r = uv_timer_init(&worker->loop, &sock->timer);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->timer, sock);
 
 	if (isc__nm_closing(sock)) {
@@ -436,13 +436,13 @@ isc__nm_async_udplisten(isc__networker_t *worker, isc__netievent_t *ev0) {
 	uv_init_flags |= UV_UDP_RECVMMSG;
 #endif
 	r = uv_udp_init_ex(&worker->loop, &sock->uv_handle.udp, uv_init_flags);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_udp_init_ex, r);
 	uv_handle_set_data(&sock->uv_handle.handle, sock);
 	/* This keeps the socket alive after everything else is gone */
 	isc__nmsocket_attach(sock, &(isc_nmsocket_t *){ NULL });
 
 	r = uv_timer_init(&worker->loop, &sock->timer);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->timer, sock);
 
 	LOCK(&sock->parent->lock);
@@ -854,11 +854,11 @@ udp_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
 	atomic_store(&sock->connecting, true);
 
 	r = uv_udp_init(&worker->loop, &sock->uv_handle.udp);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_udp_init, r);
 	uv_handle_set_data(&sock->uv_handle.handle, sock);
 
 	r = uv_timer_init(&worker->loop, &sock->timer);
-	RUNTIME_CHECK(r == 0);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->timer, sock);
 
 	if (isc__nm_closing(sock)) {