netdev - Re: [Patch net 00/15] net_sched: remove RCU callbacks from TC

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] [day] [month] [year] [list]

Date:   Thu, 26 Oct 2017 12:10:14 -0700
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Cc:     David Miller <davem@...emloft.net>,
        Linux Kernel Network Developers <netdev@...r.kernel.org>,
        Jamal Hadi Salim <jhs@...atatu.com>,
        John Fastabend <john.fastabend@...il.com>,
        Chris Mi <chrism@...lanox.com>
Subject: Re: [Patch net 00/15] net_sched: remove RCU callbacks from TC

On Thu, Oct 26, 2017 at 6:58 AM, Paul E. McKenney
<paulmck@...ux.vnet.ibm.com> wrote:
>
> So when removing an entire chain, you flush any queued workqueue handlers
> to make sure that any operations using elements on that chain have also
> completed, correct?  This might also motivate the rcu_barrier() calls.

Yes, we can only free it after all pending RCU callbacks and works finish,
because they are in the same chain and we are freeing the head of the
chain in tcf_block_put().

>
> Seems to me that your proposed patch is at least worth a try, then.
>

Thank you! Then it makes some basic sense. I did a quick test and
don't see any crash or lockdep warning.