From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Roland Franke" <fli4l@franke-prem.de>
Subject: Re: iproute2 4.14.1 tc class add come to kernel-panic
Date: Tue, 30 Jan 2018 18:46:52 +0100
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Cc: "Eric Dumazet" <eric.dumazet@gmail.com>,
        "Linux Kernel Network Developers" <netdev@vger.kernel.org>
To: "Cong Wang" <xiyou.wangcong@gmail.com>,
        "Stephen Hemminger" <stephen@networkplumber.org>
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Hello,

> On Mon, Jan 29, 2018 at 9:03 AM, Cong Wang <xiyou.wangcong@gmail.com> 
> wrote:
>> On Mon, Jan 29, 2018 at 8:00 AM, Stephen Hemminger
>> <stephen@networkplumber.org> wrote:
>>> On Mon, 29 Jan 2018 16:18:07 +0100
>>> "Roland Franke" <fli4l@franke-prem.de> wrote:
>>>
>>>> Hello,
>>>>
>>>> > To: Roland Franke ; netdev@vger.kernel.org
>>>> > Subject: Re: BUG: iproute2 4.14.1 tc class add come to kernel-panic
>>>> >>
>>>> >> tc qdisc add dev eth0 root handle 20: htb default 4 r2q 1
>>>> >> tc class add dev eth0 parent 20: classid 20:7 htb rate 10000kbit
>>>> >> tc qdisc add dev eth0 parent 20:7 sfq perturb 10
>>>> >> tc class add dev eth0 parent 20:7 classid 20:1 htb rate 200kbit ceil
>>>> >> 10000kbit prio 0
>>>> >>
>>>> >> I become an Kernel-panic with the following output:
>>>> >> kern.err kernel: BUG: scheduling while atomic: tc/1036/0x00000200
>>>> >
>>>>
>>>> > Would you have a stack trace to share with us ?
>>>>
>>>> As i will be an absolute newby here, i will not know how to
>>>> get the stack trace out.
>>>> When i will get some information how to get this, i can try to
>>>> give you this information.
>>>> But by my last tests i made the first 3 commands on an console
>>>> and had no error. Only by typing the last line i will get the error and
>>>> here i get actally only the "kern.err kernel: BUG: ....." message.
>>>>
>>>> Roland
>>>
>>> It generates this with lockdep (on 4.15)
>>>
>>> [  151.355076] HTB: quantum of class 200007 is big. Consider r2q change.
>>
>>
>> We hold qdisc tree spinlock but call rcu_barrier() in
>> mini_qdisc_pair_swap()...

> Well, not min_qdisc things, but it should be resolved by:

> commit efbf78973978b0d25af59bc26c8013a942af6e64
> Author: Cong Wang <xiyou.wangcong@gmail.com>
> Date:   Mon Dec 4 10:48:18 2017 -0800

>     net_sched: get rid of rcu_barrier() in tcf_block_put_ext()

Against what kernel-version was this be made?
patch from https://patchwork.ozlabs.org/patch/844372/
will not fit against kernel 4.14.15