diff --git a/lib/create.c b/lib/create.c
index 6eed2638f..c64e755be 100644
--- a/lib/create.c
+++ b/lib/create.c
@@ -202,13 +202,11 @@ disk_create_raw (guestfs_h *g, const char *filename, int64_t size,
     }
 #else
     /* Slow emulation of posix_fallocate on platforms which don't have it. */
-    char buffer[BUFSIZ];
+    char buffer[BUFSIZ] = {0};
     size_t remaining = size;
     size_t n;
     ssize_t r;
 
-    memset (buffer, 0, sizeof buffer);
-
     while (remaining > 0) {
       n = remaining > sizeof buffer ? sizeof buffer : remaining;
       r = write (fd, buffer, n);