Re: net: suspicious RCU usage in nf_hook

From: Eric Dumazet
Date: Tue Jan 31 2017 - 10:46:08 EST

On Mon, 2017-01-30 at 22:19 -0800, Cong Wang wrote:

> The context is process context (TX path before hitting qdisc), and
> BH is not disabled, so in_interrupt() doesn't catch it. Hmm, this
> makes me thinking maybe we really need to disable BH in this
> case for nf_hook()? But it is called in RX path too, and BH is
> already disabled there.

ipt_do_table() and similar netfilter entry points disable BH.

Maybe it is done too late.