From f72ae60881ff685004d7de7152517607fcd9968f Mon Sep 17 00:00:00 2001 From: Dan Drown Date: Wed, 16 Aug 2023 20:09:43 -0500 Subject: [PATCH] usb: cdc-acm: move ldisc dcd notification outside of acm's read lock 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 Acked-by: Oliver Neukum Link: https://lore.kernel.org/r/ZN1zV/zjPgpGlHXo@vps3.drown.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 9b34199..dfb28c7 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -319,23 +319,24 @@ 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; if (difference & USB_CDC_SERIAL_STATE_DSR) acm->iocount.dsr++; - if (difference & USB_CDC_SERIAL_STATE_DCD) { - if (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); - } - } + if (difference & USB_CDC_SERIAL_STATE_DCD) acm->iocount.dcd++; - } if (newctrl & USB_CDC_SERIAL_STATE_BREAK) { acm->iocount.brk++; tty_insert_flip_char(&acm->port, 0, TTY_BREAK); -- 2.7.4