4.18-stable review patch. If anyone has any objections, please let me know.
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From: Tobias Herzog t-herzog@gmx.de
commit dae3ddba36f8c337fb59cef07d564da6fc9b7551 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
--- drivers/usb/class/cdc-acm.c | 1 - 1 file changed, 1 deletion(-)
--- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -354,7 +354,6 @@ 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);