On Fri, Sep 08, 2023 at 08:37:12PM -0400, Sasha Levin wrote: > 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; This is a fix for a commit in 6.6-rc1 (3b563b901eef ("usb: cdc-acm: add PPS support")) so a backport of it makes no sense. Please drop. Johan
