diff --git a/cmds-device.c b/cmds-device.c
index 3a10438b..c588a6e0 100644
--- a/cmds-device.c
+++ b/cmds-device.c
@@ -126,6 +126,7 @@ static int cmd_add_dev(int argc, char **argv)
 			goto error_out;
 		}
 
+		memset(&ioctl_args, 0, sizeof(ioctl_args));
 		strncpy_null(ioctl_args.name, path);
 		res = ioctl(fdmnt, BTRFS_IOC_ADD_DEV, &ioctl_args);
 		e = errno;
@@ -175,6 +176,7 @@ static int cmd_rm_dev(int argc, char **argv)
 			ret++;
 			continue;
 		}
+		memset(&arg, 0, sizeof(arg));
 		strncpy_null(arg.name, argv[i]);
 		res = ioctl(fdmnt, BTRFS_IOC_RM_DEV, &arg);
 		e = errno;
@@ -312,7 +314,8 @@ static int cmd_ready_dev(int argc, char **argv)
 		goto out;
 	}
 
-	strncpy(args.name, path, BTRFS_PATH_NAME_MAX);
+	memset(&args, 0, sizeof(args));
+	strncpy_null(args.name, path);
 	ret = ioctl(fd, BTRFS_IOC_DEVICES_READY, &args);
 	if (ret < 0) {
 		fprintf(stderr, "ERROR: unable to determine if the device '%s'"
diff --git a/cmds-filesystem.c b/cmds-filesystem.c
index ccf89c66..dcd3f479 100644
--- a/cmds-filesystem.c
+++ b/cmds-filesystem.c
@@ -1270,6 +1270,7 @@ static int cmd_resize(int argc, char **argv)
 	}
 
 	printf("Resize '%s' of '%s'\n", path, amount);
+	memset(&args, 0, sizeof(args));
 	strncpy_null(args.name, amount);
 	res = ioctl(fd, BTRFS_IOC_RESIZE, &args);
 	e = errno;
diff --git a/cmds-subvolume.c b/cmds-subvolume.c
index dfc3f1f3..e88a6e6e 100644
--- a/cmds-subvolume.c
+++ b/cmds-subvolume.c
@@ -357,6 +357,7 @@ again:
 	printf("Delete subvolume (%s): '%s/%s'\n",
 		commit_mode == 2 || (commit_mode == 1 && cnt + 1 == argc)
 		? "commit" : "no-commit", dname, vname);
+	memset(&args, 0, sizeof(args));
 	strncpy_null(args.name, vname);
 	res = ioctl(fd, BTRFS_IOC_SNAP_DESTROY, &args);
 	e = errno;
diff --git a/utils.c b/utils.c
index 087f3715..591b2a1d 100644
--- a/utils.c
+++ b/utils.c
@@ -1409,8 +1409,8 @@ int btrfs_register_one_device(const char *fname)
 			strerror(errno));
 		return -errno;
 	}
-	strncpy(args.name, fname, BTRFS_PATH_NAME_MAX);
-	args.name[BTRFS_PATH_NAME_MAX-1] = 0;
+	memset(&args, 0, sizeof(args));
+	strncpy_null(args.name, fname);
 	ret = ioctl(fd, BTRFS_IOC_SCAN_DEV, &args);
 	e = errno;
 	if (ret < 0) {