Re: arping stuck with ENOBUFS in 4.19.150

[Yunsheng Lin <linyunsheng@huawei.com>]

On 2020/10/29 23:18, David Ahern wrote:
> On 10/29/20 8:10 AM, Joakim Tjernlund wrote:
>> OK, bisecting (was a bit of a bother since we merge upstream releases into our tree, is there a way to just bisect that?)
>>
>> Result was commit "net: sch_generic: aviod concurrent reset and enqueue op for lockless qdisc"  (749cc0b0c7f3dcdfe5842f998c0274e54987384f)
>>
>> Reverting that commit on top of our tree made it work again. How to fix?
> 
> Adding the author of that patch (linyunsheng@huawei.com) to take a look.
> 
> 
>>
>>  Jocke
>>  
>> On Mon, 2020-10-26 at 12:31 -0600, David Ahern wrote:
>>>
>>> On 10/26/20 6:58 AM, Joakim Tjernlund wrote:
>>>> Ping  (maybe it should read "arping" instead :)
>>>>
>>>>  Jocke
>>>>
>>>> On Thu, 2020-10-22 at 17:19 +0200, Joakim Tjernlund wrote:
>>>>> strace arping -q -c 1 -b -U  -I eth1 0.0.0.0
>>>>> ...
>>>>> sendto(3, "\0\1\10\0\6\4\0\1\0\6\234\v\6 \v\v\v\v\377\377\377\377\377\377\0\0\0\0", 28, 0, {sa_family=AF_PACKET, proto=0x806, if4, pkttype=PACKET_HOST, addr(6)={1, ffffffffffff},
>>>>> 20) = -1 ENOBUFS (No buffer space available)
>>>>> ....
>>>>> and then arping loops.
>>>>>
>>>>> in 4.19.127 it was:
>>>>> sendto(3, "\0\1\10\0\6\4\0\1\0\6\234\5\271\362\n\322\212E\377\377\377\377\377\377\0\0\0\0", 28, 0, {​sa_family=AF_PACKET, proto=0x806, if4, pkttype=PACKET_HOST, addr(6)={​1,
>>>>> ffffffffffff}​, 20) = 28
>>>>>
>>>>> Seems like something has changed the IP behaviour between now and then ?
>>>>> eth1 is UP but not RUNNING and has an IP address.

"eth1 is UP but not RUNNING" usually mean user has configure the netdev as up,
but the hardware has not detected a linkup yet.

Also What is the output of "ethtool eth1"?

It would be good to see the status of netdev before and after executing arping cmd
too.

Thanks.

>>>>>
>>>>>  Jocke
>>>>
>>>
>>> do a git bisect between the releases to find out which commit is causing
>>> the change in behavior.

unfortunately, I did not reproduce the above problem in 4.19.150 too.

root@(none)$ arping -q -c 1 -b -U  -I eth0 0.0.0.0
root@(none)$ arping -v
ARPing 2.21, by Thomas Habets <thomas@habets.se>
usage: arping [ -0aAbdDeFpPqrRuUv ] [ -w <sec> ] [ -W <sec> ] [ -S <host/ip> ]
              [ -T <host/ip ] [ -s <MAC> ] [ -t <MAC> ] [ -c <count> ]
              [ -C <count> ] [ -i <interface> ] [ -m <type> ] [ -g <group> ]
              [ -V <vlan> ] [ -Q <priority> ] <host/ip/MAC | -B>
For complete usage info, use --help or check the manpage.
root@(none)$ cat /proc/version
Linux version 4.19.150 (linyunsheng@ubuntu) (gcc version 5.4.0 20160609 (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.12)) #4 SMP PREEMPT Fri Oct 30 09:22:06 CST 2020



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