diff --git a/src/util-memmap.c b/src/util-memmap.c
index a106ef2..31445f7 100644
--- a/src/util-memmap.c
+++ b/src/util-memmap.c
@@ -55,6 +55,9 @@ OBJECT_IMPLEMENT_GETTER(memmap, data, void *);
 struct memmap *
 memmap_new(int fd, size_t sz)
 {
+	if (sz == 0)
+		return NULL;
+
 	_unref_(memmap) *memmap = memmap_create(NULL);
 
 	void *map = mmap(NULL, sz, PROT_READ, MAP_PRIVATE, fd, 0);