diff --git a/drivers/s390/char/monwriter.c b/drivers/s390/char/monwriter.c
index 76c158c41510..4f1a69c9d81d 100644
--- a/drivers/s390/char/monwriter.c
+++ b/drivers/s390/char/monwriter.c
@@ -61,7 +61,7 @@ static int monwrite_diag(struct monwrite_hdr *myhdr, char *buffer, int fcn)
 	struct appldata_product_id id;
 	int rc;
 
-	strncpy(id.prod_nr, "LNXAPPL", 7);
+	memcpy(id.prod_nr, "LNXAPPL", 7);
 	id.prod_fn = myhdr->applid;
 	id.record_nr = myhdr->record_num;
 	id.version_nr = myhdr->version;