From: Dan Drown <dan-netdev@xxxxxxxxx> [ Upstream commit f72ae60881ff685004d7de7152517607fcd9968f ] dcd_change notification call moved outside of the acm->read_lock to protect any future tty ldisc that calls wait_serial_change() Signed-off-by: Dan Drown <dan-netdev@xxxxxxxxx> Acked-by: Oliver Neukum <oneukum@xxxxxxxx> Link: https://lore.kernel.org/r/ZN1zV/zjPgpGlHXo@xxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/usb/class/cdc-acm.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 11da5fb284d0a..ca51230f44409 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -318,6 +318,16 @@ static void acm_process_notification(struct acm *acm, unsigned char *buf) } difference = acm->ctrlin ^ newctrl; + + if ((difference & USB_CDC_SERIAL_STATE_DCD) && acm->port.tty) { + struct tty_ldisc *ld = tty_ldisc_ref(acm->port.tty); + if (ld) { + if (ld->ops->dcd_change) + ld->ops->dcd_change(acm->port.tty, newctrl & USB_CDC_SERIAL_STATE_DCD); + tty_ldisc_deref(ld); + } + } + spin_lock_irqsave(&acm->read_lock, flags); acm->ctrlin = newctrl; acm->oldcount = acm->iocount; -- 2.40.1
