Commit 8686f337 authored Sep 22, 2018 by Tobias Herzog Committed by Greg Kroah-Hartman Nov 10, 2018

cdc-acm: do not reset notification buffer index upon urb unlinking



commit dae3ddba upstream.

Resetting the write index of the notification buffer on urb unlink (e.g.
closing a cdc-acm device from userspace) may lead to wrong interpretation
of further received notifications, in case the index is not 0 when urb
unlink happens (i.e. when parts of a notification already have been
transferred). On the device side there is no "reset" of the notification
transimission and thus we would get out of sync with the device.

Signed-off-by: Tobias Herzog <t-herzog@gmx.de>
Acked-by: Oliver Neukum <oneukum@suse.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent f0e3b74a

drivers/usb/class/cdc-acm.c

+0 −1

Original line number	Diff line number	Diff line
		@@ -367,7 +367,6 @@ static void acm_ctrl_irq(struct urb *urb)
		case -ENOENT:
		case -ESHUTDOWN:
		/* this urb is terminated, clean up */
		acm->nb_index = 0;
		dev_dbg(&acm->control->dev,
		"%s - urb shutting down with status: %d\n",
		__func__, status);