USB: wdm: handle IO errors in wdm_wwan_port_start

In case submitting the URB fails we must undo
what we've done so far.

Fixes: cac6fb015f71 ("usb: class: cdc-wdm: WWAN framework integration")
Cc: stable <stable@kernel.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/20250401084749.175246-2-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 86ee39db013f3932cf96635ddbde3a86b5c9309a..eb86d1c9b4a44852df1ca991ddf6b0de48f0eec7 100644 (file)
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -829,6 +829,7 @@ static struct usb_class_driver wdm_class = {
 static int wdm_wwan_port_start(struct wwan_port *port)
 {
        struct wdm_device *desc = wwan_port_get_drvdata(port);
+       int rv;
 
        /* The interface is both exposed via the WWAN framework and as a
         * legacy usbmisc chardev. If chardev is already open, just fail
@@ -848,7 +849,15 @@ static int wdm_wwan_port_start(struct wwan_port *port)
        wwan_port_txon(port);
 
        /* Start getting events */
-       return usb_submit_urb(desc->validity, GFP_KERNEL);
+       rv = usb_submit_urb(desc->validity, GFP_KERNEL);
+       if (rv < 0) {
+               wwan_port_txoff(port);
+               desc->manage_power(desc->intf, 0);
+               /* this must be last lest we race with chardev open */
+               clear_bit(WDM_WWAN_IN_USE, &desc->flags);
+       }
+
+       return rv;
 }
 
 static void wdm_wwan_port_stop(struct wwan_port *port)