Re: [PATCH nf] netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state

[Florian Westphal <fw@strlen.de>]

Florian Westphal <fw@strlen.de> wrote:
> sashiko reports: "nfnl_log_net_exit() calls nf_log_unset(), which
> clears the logger pointer without an RCU grace period.  Immediately after,
> ops_free_list() frees the per-net state while concurrent packets might
> still be executing nf_log_packet() under rcu_read_lock()."
> 
> Clear the pointer via .pre_exit to make sure rcu readers have completed
> before pernet storage is free'd.  The change in nf_log_syslog.c is only
> done for consistency: it doesn't use pernet data.

Forgot to add:
Fixes: 9368a53c471b ("netfilter: nfnetlink_log: add net namespace support for nfnetlink_log")

The sashiko review can be ignored, its correct but there is a pending
ebt_nflog patch that resolves the issue.