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/bus.c b/drivers/usb/serial/bus.c
index 6f91eb9..b53a286 100644
--- a/drivers/usb/serial/bus.c
+++ b/drivers/usb/serial/bus.c
@@ -38,15 +38,6 @@
return 0;
}
-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, "%d\n", port->port_number);
-}
-static DEVICE_ATTR_RO(port_number);
-
static int usb_serial_device_probe(struct device *dev)
{
struct usb_serial_driver *driver;
@@ -73,18 +64,10 @@
goto exit_with_autopm;
}
- retval = device_create_file(dev, &dev_attr_port_number);
- if (retval) {
- if (driver->port_remove)
- driver->port_remove(port);
- goto exit_with_autopm;
- }
-
minor = port->minor;
tty_dev = tty_register_device(usb_serial_tty_driver, minor, dev);
if (IS_ERR(tty_dev)) {
retval = PTR_ERR(tty_dev);
- device_remove_file(dev, &dev_attr_port_number);
if (driver->port_remove)
driver->port_remove(port);
goto exit_with_autopm;
@@ -123,8 +106,6 @@
minor = port->minor;
tty_unregister_device(usb_serial_tty_driver, minor);
- device_remove_file(&port->dev, &dev_attr_port_number);
-
driver = port->serial->type;
if (driver->port_remove)
retval = driver->port_remove(port);
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);
}