From: Konstantin Khlebnikov <khlebni...@yandex-team.ru>
Date: Tue, 15 Aug 2017 16:35:21 +0300
> Traffic filters could keep direct pointers to classes in classful qdisc,
> thus qdisc destruction first removes all filters before freeing classes.
> Class destruction methods also tries to free attached filters but now
> this isn't safe because tcf_block_put() unlike to tcf_destroy_chain()
> cannot be called second time.
>
> This patch set class->block to NULL after first tcf_block_put() and
> turn second call into no-op.
>
> Signed-off-by: Konstantin Khlebnikov <khlebni...@yandex-team.ru>
> Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infractructure")
Applied and queued up for -stable.
