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: [PATCH] cdc-acm: do not reset notification buffer index upon urb unlinking
Git-commit: dae3ddba36f8c337fb59cef07d564da6fc9b7551
Patch-mainline: v4.19
References: bsc#1051510
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
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