USB: cdc-acm: fix open and suspend race

We must not do the usb_autopm_put_interface() before submitting the read
urbs or we might end up doing I/O to a suspended device.

Fixes: 088c64f81284 ("USB: cdc-acm: re-write read processing")
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 3 insertions, 4 deletions

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index c255e77282ad..74df311c8505 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -528,19 +528,15 @@ static int acm_port_activate(struct tty_port *port, struct tty_struct *tty)
         if (usb_submit_urb(acm->ctrlurb, GFP_KERNEL)) {
                 dev_err(&acm->control->dev,
                         "%s - usb_submit_urb(ctrl irq) failed\n", __func__);
-                usb_autopm_put_interface(acm->control);
                 goto error_submit_urb;
         }
 
         acm->ctrlout = ACM_CTRL_DTR | ACM_CTRL_RTS;
         if (acm_set_control(acm, acm->ctrlout) < 0 &&
             (acm->ctrl_caps & USB_CDC_CAP_LINE)) {
-                usb_autopm_put_interface(acm->control);
                 goto error_set_control;
         }
 
-        usb_autopm_put_interface(acm->control);
-
         /*
          * Unthrottle device in case the TTY was closed while throttled.
          */
@@ -552,6 +548,8 @@ static int acm_port_activate(struct tty_port *port, struct tty_struct *tty)
         if (acm_submit_read_urbs(acm, GFP_KERNEL))
                 goto error_submit_read_urbs;
 
+        usb_autopm_put_interface(acm->control);
+
         mutex_unlock(&acm->mutex);
 
         return 0;
@@ -562,6 +560,7 @@ error_submit_read_urbs:
 error_set_control:
         usb_kill_urb(acm->ctrlurb);
 error_submit_urb:
+        usb_autopm_put_interface(acm->control);
 error_get_interface:
 disconnected:
         mutex_unlock(&acm->mutex);