diff --git a/vm/os-linux.cpp b/vm/os-linux.cpp
index 0261942462c..5841673fb21 100644
--- a/vm/os-linux.cpp
+++ b/vm/os-linux.cpp
@@ -3,18 +3,18 @@
 namespace factor {
 
 const char* vm_executable_path() {
-  ssize_t bufsiz = 4096;
+  size_t bufsiz = 4096;
 
   // readlink is called in a loop with increasing buffer sizes in case
   // someone tries to run Factor from a incredibly deeply nested
   // path.
   while (true) {
     char* buf = new char[bufsiz + 1];
-    ssize_t size= readlink("/proc/self/exe", buf, bufsiz);
+    ssize_t size = readlink("/proc/self/exe", buf, bufsiz);
     if (size < 0) {
       fatal_error("Cannot read /proc/self/exe", errno);
     } else {
-      if (size < bufsiz) {
+      if (size < ((size_t) bufsiz)) {
         // Buffer was large enough, return string.
         buf[size] = '\0';
         const char* ret = safe_strdup(buf);