From: Johan Hovold Date: Tue, 19 Mar 2013 08:21:06 +0000 (+0100) Subject: USB: cdc-acm: fix device unregistration X-Git-Tag: v3.8.5~15 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5557c6706441e7ad797b8b5c95579a9a1146502b;p=thirdparty%2Fkernel%2Fstable.git USB: cdc-acm: fix device unregistration commit cb25505fc604292c70fc02143fc102f54c8595f0 upstream. Unregister tty device in disconnect as is required by the USB stack. By deferring unregistration to when the last tty reference is dropped, the parent interface device can get unregistered before the child resulting in broken hotplug events being generated when the tty is finally closed: KERNEL[2290.798128] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-1/2-1:3.1 (usb) KERNEL[2290.804589] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-1 (usb) KERNEL[2294.554799] remove /2-1:3.1/tty/ttyACM0 (tty) The driver must deal with tty callbacks after disconnect by checking the disconnected flag. Specifically, further opens must be prevented and this is already implemented. Acked-by: Oliver Neukum Cc: Oliver Neukum Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 2d92cce260d7f..35d2cf13efc34 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -600,7 +600,6 @@ static void acm_port_destruct(struct tty_port *port) dev_dbg(&acm->control->dev, "%s\n", __func__); - tty_unregister_device(acm_tty_driver, acm->minor); acm_release_minor(acm); usb_put_intf(acm->control); kfree(acm->country_codes); @@ -1418,6 +1417,8 @@ static void acm_disconnect(struct usb_interface *intf) stop_data_traffic(acm); + tty_unregister_device(acm_tty_driver, acm->minor); + usb_free_urb(acm->ctrlurb); for (i = 0; i < ACM_NW; i++) usb_free_urb(acm->wb[i].urb);