netdev - Re: [PATCH RFC] net: Fix race condition when removing qdisc

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]

Date:	Thu, 3 Mar 2016 15:58:15 -0800
From:	Tom Herbert <tom@...bertland.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	Cong Wang <xiyou.wangcong@...il.com>,
	Linux Kernel Network Developers <netdev@...r.kernel.org>,
	Lawrence Brakmo <brakmo@...com>,
	Kernel Team <kernel-team@...com>
Subject: Re: [PATCH RFC] net: Fix race condition when removing qdisc

On Thu, Mar 3, 2016 at 3:52 PM, Eric Dumazet <eric.dumazet@...il.com> wrote:
> On jeu., 2016-03-03 at 14:24 -0800, Tom Herbert wrote:
>> This a kernel based on 3.10. We believe the lockups coincide with
>> removing/readding qdiscs.
>
> You could backport 64153ce0a7b61b2a
> ("net_sched: htb: do not setup default rate estimators"),
> unless you desperately want these rate estimators...
>
> How many HTB classes do you deal with ?
>
~1500.

One think that looks odd to me is that htb_destroy_class is not doing
an rcu_free (just kfree(cl)). I'm thinking that est_timer can run
after that kfree and be accessing some of the fields in the freed
structure (at least rate_est).

Tom