patch "cdc-acm: do not reset notification buffer index upon urb unlinking" added to usb-linus

patch "cdc-acm: do not reset notification buffer index upon urb unlinking" added to usb-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

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

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From dae3ddba36f8c337fb59cef07d564da6fc9b7551 Mon Sep 17 00:00:00 2001
From: Tobias Herzog <t-herzog@gmx.de>
Date: Sat, 22 Sep 2018 22:11:10 +0200
Subject: cdc-acm: do not reset notification buffer index upon urb unlinking

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>
---
 drivers/usb/class/cdc-acm.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 1833912f7f5f..e43ea9641416 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -355,7 +355,6 @@ 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);
-- 
2.19.1