diff --git a/src/malloc/malloc.c b/src/malloc/malloc.c
index fb65ab5bb180416166c94c8eca84d6567507dd4f..d6ad90414fc799f861ed58500d56b62b611ffa6e 100644
--- a/src/malloc/malloc.c
+++ b/src/malloc/malloc.c
@@ -177,6 +177,7 @@ static struct chunk *expand_heap(size_t n)
 	return w;
 fail:
 	unlock(mal.brk_lock);
+	errno = ENOMEM;
 	return 0;
 }