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Commit d5fd650c authored by Bjørn Mork's avatar Bjørn Mork Committed by Greg Kroah-Hartman
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usb: serial: prevent suspend/resume from racing against probe/remove 



Some usb-serial drivers may access port data in their suspend/
resume functions. Such drivers must always verify the validity
of the data as both suspend and resume can be called both before
usb_serial_device_probe and after usb_serial_device_remove.

But the port data may be invalidated during port_probe and
port_remove. This patch prevents the race against suspend and
resume by disabling suspend while port_probe or port_remove is
running.

Suggested-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarBjørn Mork <bjorn@mork.no>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a1028f0a

drivers/usb/serial/bus.c

+13 −2
Original line number Diff line number Diff line
@@ -61,18 +61,23 @@ static int usb_serial_device_probe(struct device *dev) 
		goto exit;

	}



	/* make sure suspend/resume doesn't race against port_probe */

	retval = usb_autopm_get_interface(port->serial->interface);

	if (retval)

		goto exit;



	driver = port->serial->type;

	if (driver->port_probe) {

		retval = driver->port_probe(port);

		if (retval)

			goto exit;

			goto exit_with_autopm;

	}



	retval = device_create_file(dev, &dev_attr_port_number);

	if (retval) {

		if (driver->port_remove)

			retval = driver->port_remove(port);

		goto exit;

		goto exit_with_autopm;

	}



	minor = port->number;
@@ -81,6 +86,8 @@ static int usb_serial_device_probe(struct device *dev) 
		 "%s converter now attached to ttyUSB%d\n",

		 driver->description, minor);



exit_with_autopm:

	usb_autopm_put_interface(port->serial->interface);

exit:

	return retval;

}
@@ -96,6 +103,9 @@ static int usb_serial_device_remove(struct device *dev) 
	if (!port)

		return -ENODEV;



	/* make sure suspend/resume doesn't race against port_remove */

	usb_autopm_get_interface(port->serial->interface);



	device_remove_file(&port->dev, &dev_attr_port_number);



	driver = port->serial->type;
@@ -107,6 +117,7 @@ static int usb_serial_device_remove(struct device *dev) 
	dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",

		 driver->description, minor);



	usb_autopm_put_interface(port->serial->interface);

	return retval;

}