Re: [PATCH net v4] cls_u32: fix use after free in u32_destroy_key()

[Cong Wang <xiyou.wangcong@gmail.com>]

On Mon, Feb 5, 2018 at 1:23 PM, Paolo Abeni <pabeni@redhat.com> wrote:
> The problem is that the htnode is freed before the linked knodes and the
> latter will try to access the first at u32_destroy_key() time.
> This change addresses the issue using the htnode refcnt to guarantee
> the correct free order. While at it also add a RCU annotation,
> to keep sparse happy.
>
> v1 -> v2: use rtnl_derefence() instead of RCU read locks
> v2 -> v3:
>   - don't check refcnt in u32_destroy_hnode()
>   - cleaned-up u32_destroy() implementation
>   - cleaned-up code comment
> v3 -> v4:
>   - dropped unneeded comment
>
> Reported-by: Li Shuang <shuali@redhat.com>
> Fixes: c0d378ef1266 ("net_sched: use tcf_queue_work() in u32 filter")
> Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Acked-by: Cong Wang <xiyou.wangcong@gmail.com>

Thanks.