From 9397940ed812b942c520e0c25ed4b2c64d57e8b9 Mon Sep 17 00:00:00 2001

From: Oliver Neukum <oneukum@suse.com>

Date: Thu, 4 Oct 2018 15:49:06 +0200

Subject: [PATCH] cdc-acm: fix race between reset and control messaging

Git-commit: 9397940ed812b942c520e0c25ed4b2c64d57e8b9

Patch-mainline: v4.19

References: bsc#1051510

If a device splits up a control message and a reset() happens

between the parts, the message is lost and already recieved parts

must be dropped.

Signed-off-by: Oliver Neukum <oneukum@suse.com>

Fixes: 1aba579f3cf51 ("cdc-acm: handle read pipe errors")

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 insertion(+)

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c

index bc03b0a690b4..1833912f7f5f 100644

--- a/drivers/usb/class/cdc-acm.c

+++ b/drivers/usb/class/cdc-acm.c

@@ -1642,6 +1642,7 @@ static int acm_pre_reset(struct usb_interface *intf)

 	struct acm *acm = usb_get_intfdata(intf);

 	clear_bit(EVENT_RX_STALL, &acm->flags);

+	acm->nb_index = 0; /* pending control transfers are lost */

 	return 0;

 }

-- 

2.19.1