From: Paolo Abeni <pab...@redhat.com>
Date: Wed, 20 Feb 2019 18:18:12 +0100
> When a netdevice is unregistered, we flush the relevant exception
> via rt6_sync_down_dev() -> fib6_ifdown() -> fib6_del() -> fib6_del_route().
>
> Finally, we end-up calling rt6_remove_exception(), where we release
> the relevant dst, while we keep the references to the related fib6_info and
> dev. Such references should be released later when the dst will be
> destroyed.
>
> There are a number of caches that can keep the exception around for an
> unlimited amount of time - namely dst_cache, possibly even socket cache.
> As a result device registration may hang, as demonstrated by this script:
...
> Fixes: 93531c674315 ("net/ipv6: separate handling of FIB entries from dst
> based routes")
> Signed-off-by: Paolo Abeni <pab...@redhat.com>
Applied and queued up for -stable, thanks.
