[PATCH] USB: core: Fix potental Null Pointer dereference

[Yizhuo]

Inside function usb_device_is_owned(), usb_hub_to_struct_hub()
could return NULL but there's no check before its dereference,
which is potentially unsafe.

Signed-off-by: Yizhuo <yzhai003@xxxxxxx>
---
 drivers/usb/core/hub.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 236313f41f4a..8d628c8e0c1b 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1977,7 +1977,7 @@ bool usb_device_is_owned(struct usb_device *udev)
 	if (udev->state == USB_STATE_NOTATTACHED || !udev->parent)
 		return false;
 	hub = usb_hub_to_struct_hub(udev->parent);
-	return !!hub->ports[udev->portnum - 1]->port_owner;
+	return hub && !!hub->ports[udev->portnum - 1]->port_owner;
 }
 
 static void recursively_mark_NOTATTACHED(struct usb_device *udev)
-- 
2.17.1