diff --git a/include/udx.h b/include/udx.h
index 757710d..666eb6b 100644
--- a/include/udx.h
+++ b/include/udx.h
@@ -6,6 +6,7 @@ extern "C" {
 #endif
 
 #include <math.h>
+#include <stdalign.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <uv.h>
@@ -428,7 +429,8 @@ struct udx_packet_s {
   bool is_app_limited;    // was throughput app-limited (vs network limited) at the time the packet was transmitted?
 
   // just alloc it in place here, easier to manage
-  uint8_t header[UDX_HEADER_SIZE];
+  alignas(4) uint8_t header[UDX_HEADER_SIZE];
+
   uint16_t nwbufs;          // nwbufs = nbufs - 1
   uint16_t nwbufs_capacity; // initially ARRAY_SIZEOF(wbuf_sml), used for realloc
 
diff --git a/src/udx.c b/src/udx.c
index 2bf3396..5fded99 100644
--- a/src/udx.c
+++ b/src/udx.c
@@ -489,7 +489,8 @@ send_probe (udx_stream_t *stream) {
 
   // todo: send a data packet with seq=remote_acked-1 instead
 
-  uint8_t header[20];
+  alignas(4) uint8_t header[20];
+
   udx_write_header(header, stream, UDX_HEADER_HEARTBEAT);
 
   // fast path
@@ -2655,7 +2656,9 @@ stream_on_destroy_send (udx_stream_t *stream) {
 
 static void
 _stream_on_destroy_send (uv_udp_send_t *req, int status) {
-  debug_printf("udx destroy send: err=%s\n", uv_strerror(status));
+  if (status < 0) {
+    debug_printf("udx destroy send: err=%s\n", uv_strerror(status));
+  }
   udx_stream_t *stream = req->data;
   stream_on_destroy_send(stream);
   free(req);
@@ -2682,7 +2685,8 @@ udx_stream_destroy (udx_stream_t *stream) {
 
   // write destroy packet
 
-  uint8_t header[20];
+  alignas(4) uint8_t header[20];
+
   udx_write_header(header, stream, UDX_HEADER_DESTROY);
   stream->seq++;
 
diff --git a/test/stream-bbr-state.c b/test/stream-bbr-state.c
index d498d3a..f58b9ef 100644
--- a/test/stream-bbr-state.c
+++ b/test/stream-bbr-state.c
@@ -166,11 +166,13 @@ send_periodic (uv_timer_t *timer) {
 static void
 send_ack_slow (udx_stream_write_t *r, int status, int unordered) {
   // printf("send_ack (slow)\n");
+  free(r);
 }
 
 static void
 send_ack_fast (udx_stream_write_t *r, int status, int unordered) {
   // printf("send_ack (fast) elapsed=%ld\n", uv_now(&loop) - start_ms);
+  free(r);
 }
 
 static void
diff --git a/test/stream-change-remote.c b/test/stream-change-remote.c
index af41b65..2bc4f83 100644
--- a/test/stream-change-remote.c
+++ b/test/stream-change-remote.c
@@ -162,7 +162,9 @@ main () {
   e = udx_stream_connect(&dstream, &dsock, 3, (struct sockaddr *) &caddr);
   assert(e == 0);
 
-  uv_buf_t buf = uv_buf_init(malloc(NBYTES_TO_SEND), NBYTES_TO_SEND);
+  char *data = malloc(NBYTES_TO_SEND);
+
+  uv_buf_t buf = uv_buf_init(data, NBYTES_TO_SEND);
 
   write_hash = hash(write_hash, (uint8_t *) buf.base, buf.len);
 
@@ -177,6 +179,7 @@ main () {
   printf("read_hash=%lu write_hash=%lu\n", read_hash, write_hash);
 
   free(req);
+  free(data);
 
   return 0;
 }
diff --git a/test/stream-destroy-before-connect.c b/test/stream-destroy-before-connect.c
index 00e2907..6e3d9cb 100644
--- a/test/stream-destroy-before-connect.c
+++ b/test/stream-destroy-before-connect.c
@@ -20,6 +20,9 @@ main () {
   e = udx_stream_destroy(&stream);
   assert(e == 0);
 
+  e = uv_run(&loop, UV_RUN_DEFAULT);
+  assert(e == 0);
+
   uv_loop_close(&loop);
 
   return 0;
diff --git a/test/stream-relay-force-slow-path.c b/test/stream-relay-force-slow-path.c
index fa9c660..2e492fc 100644
--- a/test/stream-relay-force-slow-path.c
+++ b/test/stream-relay-force-slow-path.c
@@ -133,7 +133,9 @@ main () {
   e = udx_stream_connect(&dstream, &dsock, 3, (struct sockaddr *) &caddr);
   assert(e == 0);
 
-  uv_buf_t buf = uv_buf_init(calloc(NBYTES_TO_SEND, 1), NBYTES_TO_SEND);
+  char *data = calloc(NBYTES_TO_SEND, 1);
+
+  uv_buf_t buf = uv_buf_init(data, NBYTES_TO_SEND);
 
   memcpy(buf.base, "hello", 5);
 
@@ -148,6 +150,7 @@ main () {
   assert(nbytes_read == NBYTES_TO_SEND && read_hash == write_hash);
 
   free(req);
+  free(data);
 
   return 0;
 }
diff --git a/test/stream-relay.c b/test/stream-relay.c
index f79346b..37ea08d 100644
--- a/test/stream-relay.c
+++ b/test/stream-relay.c
@@ -131,7 +131,9 @@ main () {
   e = udx_stream_connect(&dstream, &dsock, 3, (struct sockaddr *) &caddr);
   assert(e == 0);
 
-  uv_buf_t buf = uv_buf_init(calloc(NBYTES_TO_SEND, 1), NBYTES_TO_SEND);
+  char *data = calloc(NBYTES_TO_SEND, 1);
+
+  uv_buf_t buf = uv_buf_init(data, NBYTES_TO_SEND);
 
   memcpy(buf.base, "hello", 5);
 
@@ -146,6 +148,7 @@ main () {
   assert(nbytes_read == NBYTES_TO_SEND && read_hash == write_hash);
 
   free(req);
+  free(data);
 
   return 0;
 }
diff --git a/test/stream-write-read-multiple.c b/test/stream-write-read-multiple.c
index 4c95dca..eeac601 100644
--- a/test/stream-write-read-multiple.c
+++ b/test/stream-write-read-multiple.c
@@ -92,5 +92,8 @@ main () {
 
   assert(ack_called == 2 && total_read == buf.len * 2);
 
+  free(areq);
+  free(breq);
+
   return 0;
 }
diff --git a/test/stream-write-read-perf.c b/test/stream-write-read-perf.c
index a7722fd..e323e41 100644
--- a/test/stream-write-read-perf.c
+++ b/test/stream-write-read-perf.c
@@ -59,24 +59,24 @@ on_read (udx_stream_t *handle, ssize_t read_len, const uv_buf_t *buf) {
 }
 
 static void
-on_b_sock_close () {
+on_b_sock_close (udx_socket_t *socket) {
   printf("sending socket closing\n");
 }
 
 static void
-on_b_stream_close () {
+on_b_stream_close (udx_stream_t *stream, int status) {
   printf("sending stream closing\n");
   int e = udx_socket_close(&bsock);
   assert(e == 0 && "udx_socket_close (sender, 'b')");
 }
 
 static void
-on_a_sock_close () {
+on_a_sock_close (udx_socket_t *socket) {
   printf("receiving socket closing\n");
 }
 
 static void
-on_a_stream_close () {
+on_a_stream_close (udx_stream_t *stream, int status) {
   printf("receiving stream closing\n");
   int e = udx_socket_close(&asock);
   assert(e == 0 && "udx_socket_close (receiver, 'a')");