From: Daniel Borkmann <daniel@iogearbox•net>
To: Cong Wang <xiyou.wangcong@gmail•com>
Cc: Roi Dayan <roid@mellanox•com>,
Linux Kernel Network Developers <netdev@vger•kernel.org>,
Jiri Pirko <jiri@mellanox•com>,
John Fastabend <john.fastabend@gmail•com>
Subject: Re: [Patch net-next] net_sched: move the empty tp check from ->destroy() to ->delete()
Date: Sat, 26 Nov 2016 12:09:37 +0100 [thread overview]
Message-ID: <58396D71.8070703@iogearbox.net> (raw)
In-Reply-To: <CAM_iQpVxevmk3rgsnALC0JCqx7pOF2OBc=kpg9QDK8Cwb6P9Zw@mail.gmail.com>
On 11/26/2016 07:46 AM, Cong Wang wrote:
> On Thu, Nov 24, 2016 at 7:20 AM, Daniel Borkmann <daniel@iogearbox•net> wrote:
>>
>> Ok, strange, qdisc_destroy() calls into ops->destroy(), where ingress
>> drops its entire chain via tcf_destroy_chain(), so that will be NULL
>> eventually. The tps are freed by call_rcu() as well as qdisc itself
>> later on via qdisc_rcu_free(), where it frees per-cpu bstats as well.
>> Outstanding readers should either bail out due to if (!cl) or can still
>> process the chain until read section ends, but during that time, cl->q
>> resp. bstats should be good. Do you happen to know what's at address
>> ffff880a68b04028? I was wondering wrt call_rcu() vs call_rcu_bh(), but
>> at least on ingress (netif_receive_skb_internal()) we hold rcu_read_lock()
>> here. The KASAN report is reliably happening at this location, right?
>
> I am confused as well, I don't see how it could be related to my patch yet.
> I will take a deep look in the weekend.
Ok, I'm currently on the run. Got too late yesterday night, but I'll
write what I found in the evening today, not related to ingress though.
Cheers,
Daniel
next prev parent reply other threads:[~2016-11-26 11:31 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-24 1:58 [Patch net-next] net_sched: move the empty tp check from ->destroy() to ->delete() Cong Wang
2016-11-24 8:29 ` Roi Dayan
2016-11-24 10:14 ` Daniel Borkmann
2016-11-24 11:01 ` Roi Dayan
2016-11-24 15:20 ` Daniel Borkmann
2016-11-24 17:18 ` Daniel Borkmann
2016-11-26 6:46 ` Cong Wang
2016-11-26 11:09 ` Daniel Borkmann [this message]
2016-11-27 0:33 ` Daniel Borkmann
2016-11-27 4:47 ` Roi Dayan
2016-11-27 6:29 ` Roi Dayan
2016-11-28 2:26 ` John Fastabend
2016-11-28 2:51 ` John Fastabend
2016-11-29 6:59 ` Cong Wang
2016-11-28 2:57 ` John Fastabend
2016-11-29 6:57 ` Cong Wang
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