netdev - Re: [PATCH] net: Revert "net_sched: no need to free qdisc in RCU callback"

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAM_iQpVuLzmiEkQGJwZcrZQsAziTAbzyaszbVjLe_YeQxvYpBg@mail.gmail.com>
Date:   Wed, 20 Dec 2017 14:41:43 -0800
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     John Fastabend <john.fastabend@...il.com>
Cc:     Jiri Pirko <jiri@...nulli.us>, David Miller <davem@...emloft.net>,
        Jakub Kicinski <kubakici@...pl>,
        Linux Kernel Network Developers <netdev@...r.kernel.org>,
        Eric Dumazet <eric.dumazet@...il.com>
Subject: Re: [PATCH] net: Revert "net_sched: no need to free qdisc in RCU callback"

On Wed, Dec 20, 2017 at 12:09 PM, John Fastabend
<john.fastabend@...il.com> wrote:
> RCU grace period is needed for lockless qdiscs added in the commit
> c5ad119fb6c09 ("net: sched: pfifo_fast use skb_array").
>
> It is needed now that qdiscs may be lockless otherwise we risk
> free'ing a qdisc that is still in use from datapath. Additionally,
> push list cleanup into RCU callback. Otherwise we risk the datapath
> adding skbs during removal.

What about qdisc_graft() -> dev_deactivate() -> synchronize_net() ?
It doesn't work with your "lockless" patches?