CVE-2026-46165: openvswitch: vport: fix self-deadlock on release of tunnel ports

In the Linux kernel, the following vulnerability has been resolved:

openvswitch: vport: fix self-deadlock on release of tunnel ports

vports are used concurrently and protected by RCU, so netdevput() must happen after the RCU grace period. So, either in an RCU call or after the synchronizenet(). The rtnldeletelink() must happen under RTNL and so can't be executed in RCU context. Calling synchronizenet() while holding RTNL is not a good idea for performance and system stability under load in general, so calling netdevput() in RCU call is the right solution here.

However, when the device is deleted, rtnlunlock() will call netdevruntodo() and block until all the references are gone. In the current code this means that we never reach the callrcu() and the vport is never freed and the reference is never released, causing a self-deadlock on device removal.

Fix that by moving the rcucall() before the rtnlunlock(), so the scheduled RCU callback will be executed when synchronizenet() is called from the rtnlunlock()->netdevruntodo() while the RTNL itself is already released.