diff --git a/tools/vm/page_owner_sort.c b/tools/vm/page_owner_sort.c
index 77147b4..f1c055f 100644
--- a/tools/vm/page_owner_sort.c
+++ b/tools/vm/page_owner_sort.c
@@ -79,12 +79,12 @@
 	}
 }
 
-#define BUF_SIZE	1024
+#define BUF_SIZE	(128 * 1024)
 
 int main(int argc, char **argv)
 {
 	FILE *fin, *fout;
-	char buf[BUF_SIZE];
+	char *buf;
 	int ret, i, count;
 	struct block_list *list2;
 	struct stat st;
@@ -107,6 +107,11 @@
 	max_size = st.st_size / 100; /* hack ... */
 
 	list = malloc(max_size * sizeof(*list));
+	buf = malloc(BUF_SIZE);
+	if (!list || !buf) {
+		printf("Out of memory\n");
+		exit(1);
+	}
 
 	for ( ; ; ) {
 		ret = read_block(buf, BUF_SIZE, fin);