diff --git a/src/unix/ibmi.c b/src/unix/ibmi.c
index a534dfc56..be12fda87 100644
--- a/src/unix/ibmi.c
+++ b/src/unix/ibmi.c
@@ -174,7 +174,8 @@ static void iconv_a2e(const char* src, unsigned char dst[], size_t length) {
 }
 
 void init_process_title_mutex_once(void) {
-  uv_mutex_init(&process_title_mutex);
+  if (uv_mutex_init(&process_title_mutex))
+    abort();
 }
 
 static int get_ibmi_system_status(SSTS0200* rcvr) {
diff --git a/src/unix/proctitle.c b/src/unix/proctitle.c
index 9d1f00ddf..b78c250a2 100644
--- a/src/unix/proctitle.c
+++ b/src/unix/proctitle.c
@@ -39,7 +39,8 @@ static void* args_mem;
 
 
 static void init_process_title_mutex_once(void) {
-  uv_mutex_init(&process_title_mutex);
+  if (uv_mutex_init(&process_title_mutex))
+    abort();
 }