diff --git a/sys/dev/disk/dm/striped/dm_target_striped.c b/sys/dev/disk/dm/striped/dm_target_striped.c
--- a/sys/dev/disk/dm/striped/dm_target_striped.c
+++ b/sys/dev/disk/dm/striped/dm_target_striped.c
@@ -212,6 +212,7 @@
 	ret = ksnprintf(ptr, len, "%d %jd",
 		tsc->stripe_num,
 		(intmax_t)tsc->stripe_chunksize);
+	if (ret < 0 || (size_t)ret >= len) goto trunc;
 	ptr += ret;
 	len -= ret;
 
@@ -219,10 +220,12 @@
 		ret = ksnprintf(ptr, len, " %s %jd",
 			tsc->stripe_devs[i].pdev->udev_name,
 			(intmax_t)tsc->stripe_devs[i].offset);
+		if (ret < 0 || (size_t)ret >= len) goto trunc;
 		ptr += ret;
 		len -= ret;
 	}
 
+trunc:
 	return params;
 }