diff --git a/sandbox/memblock/memblock.c b/sandbox/memblock/memblock.c
index 5065ec5..3d045c6 100644
--- a/sandbox/memblock/memblock.c
+++ b/sandbox/memblock/memblock.c
@@ -2,6 +2,7 @@
 #include <stdio.h>
 #include <stdbool.h>
 #include <limits.h>
+#include <stdlib.h>
 #include <string.h>
 #include <socks/memblock.h>
 
@@ -225,7 +226,8 @@ static phys_addr_t do_alloc(size_t size)
 	}
 
 	if (allocated_base == ADDR_MAX) {
-		return 0;
+		fprintf(stderr, "memblock: cannot allocate %zu byte buffer!\n", size);
+		abort();
 	}
 
 	int status = memblock_add_range(&memblock.reserved, allocated_base, size, MEMBLOCK_ALLOC);