diff --git a/visionipc/visionbuf_cl.cc b/visionipc/visionbuf_cl.cc
index 0315d8db9..21c8c323a 100644
--- a/visionipc/visionbuf_cl.cc
+++ b/visionipc/visionbuf_cl.cc
@@ -86,7 +86,7 @@ int VisionBuf::free() {
     if (err != 0) return err;
   }
 
-  err = munmap(this->addr, this->len);
+  err = munmap(this->addr, this->mmap_len);
   if (err != 0) return err;
 
   err = close(this->fd);