USB: serial: fix port attribute-creation race
Fix attribute-creation race with userspace by using the port device
groups field to create the port attributes.
Also use %u when printing the port number, which is unsigned, even
though we do not currently support more than 128 ports per device.
Reported-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Greg Kroah-Hartman <greg@kroah.com>
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 1984237..529066b 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -687,6 +687,21 @@
drv->dtr_rts(p, on);
}
+static ssize_t port_number_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct usb_serial_port *port = to_usb_serial_port(dev);
+
+ return sprintf(buf, "%u\n", port->port_number);
+}
+static DEVICE_ATTR_RO(port_number);
+
+static struct attribute *usb_serial_port_attrs[] = {
+ &dev_attr_port_number.attr,
+ NULL
+};
+ATTRIBUTE_GROUPS(usb_serial_port);
+
static const struct tty_port_operations serial_port_ops = {
.carrier_raised = serial_port_carrier_raised,
.dtr_rts = serial_port_dtr_rts,
@@ -902,6 +917,7 @@
port->dev.driver = NULL;
port->dev.bus = &usb_serial_bus_type;
port->dev.release = &usb_serial_port_release;
+ port->dev.groups = usb_serial_port_groups;
device_initialize(&port->dev);
}