[PATCH] USB: fix oops in acm disconnect

this fixes an oops with disconnection in acm.

Signed-off-by: Oliver Neukum <oliver@neukum.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index b9fd39fd1b5b..97bdeb1c2181 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1014,8 +1014,13 @@ static void acm_disconnect(struct usb_interface *intf)
         }
 
         down(&open_sem);
+        if (!usb_get_intfdata(intf)) {
+                up(&open_sem);
+                return;
+        }
         acm->dev = NULL;
-        usb_set_intfdata (intf, NULL);
+        usb_set_intfdata(acm->control, NULL);
+        usb_set_intfdata(acm->data, NULL);
 
         tasklet_disable(&acm->urb_task);
 
@@ -1036,7 +1041,7 @@ static void acm_disconnect(struct usb_interface *intf)
         for (i = 0; i < ACM_NRB; i++)
                 usb_buffer_free(usb_dev, acm->readsize, acm->rb[i].base, acm->rb[i].dma);
 
-        usb_driver_release_interface(&acm_driver, acm->data);
+        usb_driver_release_interface(&acm_driver, intf == acm->control ? acm->data : intf);
 
         if (!acm->used) {
                 acm_tty_unregister(acm);