USB: serial: fix potential runtime pm imbalance at device remove (c14829fa) · Commits · 戴 / test

Only call usb_autopm_put_interface() if the corresponding usb_autopm_get_interface() was successful. This prevents a potential runtime PM counter imbalance should usb_autopm_get_interface() fail. Note that the USB PM usage counter is reset when the interface is unbound, but that the runtime PM counter may be left unbalanced. Also add comment on why we don't need to worry about racing resume/suspend on autopm_get failures. Fixes: ("usb: serial: prevent suspend/resume from racing against probe/remove") Signed-off-by:

Johan Hovold <jhovold@gmail.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/bus.c

+11 −3

Original line number	Diff line number	Diff line
		@@ -97,13 +97,19 @@ static int usb_serial_device_remove(struct device *dev)
		struct usb_serial_port *port;
		int retval = 0;
		int minor;
		int autopm_err;

		port = to_usb_serial_port(dev);
		if (!port)
		return -ENODEV;

		/* make sure suspend/resume doesn't race against port_remove */
		usb_autopm_get_interface(port->serial->interface);
		/*
		* Make sure suspend/resume doesn't race against port_remove.
		*
		* Note that no further runtime PM callbacks will be made if
		* autopm_get fails.
		*/
		autopm_err = usb_autopm_get_interface(port->serial->interface);

		minor = port->minor;
		tty_unregister_device(usb_serial_tty_driver, minor);
		@@ -117,7 +123,9 @@ static int usb_serial_device_remove(struct device *dev)
		dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
		driver->description, minor);

		if (!autopm_err)
		usb_autopm_put_interface(port->serial->interface);

		return retval;
		}

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