usb: roles: fix a potential use after free

commit 1848a543191ae32e558bb0a5974ae7c38ebd86fc upstream.

Free the sw structure only after we are done using it.
This patch just moves the put_device() down a bit to avoid the
use after free.

Fixes: 5c54fcac9a9d ("usb: roles: Take care of driver module reference counting")
Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Peter Chen <peter.chen@nxp.com>
Cc: stable <stable@vger.kernel.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: linux-usb@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20191124142236.25671-1-wenyang@linux.alibaba.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
index 94b4e7d..97e3d75 100644 (file)
--- a/drivers/usb/roles/class.c
+++ b/drivers/usb/roles/class.c
@@ -169,8 +169,8 @@ EXPORT_SYMBOL_GPL(fwnode_usb_role_switch_get);
 void usb_role_switch_put(struct usb_role_switch *sw)
 {
        if (!IS_ERR_OR_NULL(sw)) {
-               put_device(&sw->dev);
                module_put(sw->dev.parent->driver->owner);
+               put_device(&sw->dev);
        }
 }
 EXPORT_SYMBOL_GPL(usb_role_switch_put);