[Dnsmasq-discuss] [BUG] RA are sent too fast and slows down the machine

Vladislav Grishenko themiron.ru at gmail.com
Wed Aug 28 12:25:16 BST 2019


Hi, Petr,

Just worrying, isn't this bug a side effect of previous interface-related binding patch we're talking about?
If yes, since it's not in upstream, it can be quite tricky to reproduce it on vanilla sources.

Best Regards, Vladislav Grishenko

-----Original Message-----
From: Dnsmasq-discuss <dnsmasq-discuss-bounces at lists.thekelleys.org.uk> On Behalf Of Petr Mensik
Sent: Wednesday, August 28, 2019 12:11 PM
To: dnsmasq-discuss at lists.thekelleys.org.uk
Subject: Re: [Dnsmasq-discuss] [BUG] RA are sent too fast and slows down the machine

Hi Iain,

of course. I am sorry, forgot to add a link as intended[1]. Used base report from Network Manager tester report. I added it to Fedora bug mentioned, but forgot to add script itself. At least to me, it produces tens of RA announces.

Regards,
Petr

[1]
https://github.com/InfrastructureServices/dnsmasq-tests/blob/master/bz1739797.sh

On 8/27/19 10:45 AM, Iain Lane wrote:
> On Wed, Aug 21, 2019 at 08:59:07PM +0200, Petr Mensik wrote:
>> Hi Simon and Maarten,
>>
>> we discovered when playing with NetworkManager-ci [1], that lastest 
>> release is somehow broken. Test running dnsmasq are quite slow on 
>> latest release.
>>
>> I have created repeatable started script that reproduces it. Then 
>> used git bisect to find when it was broken. It seems fast sending 
>> were intentional in commit 0a496f059c1e9 [2], but maybe way it 
>> affects the system were underestimated. It is significant for systems 
>> that hit such issue. I think it has to be fixed to slow it down to 
>> short time interval, not endless loop. Reported as Fedora bug [3].
> 
> Thanks for this Petr. Would you be able to share the script you've 
> used, so that perhaps an upstream developer could recreate the bug?
> 
> Mainly I wanted to chime in and say that (in addition to the other 
> instance referenced), we found this in the NetworkManager testsuite in 
> Ubuntu. I didn't come up with a nice reproducer at the time, but we 
> did identify the same commit and we've reverted it in Ubuntu. I posted 
> on the ML back then but we didn't get much traction and I didn't 
> follow up very aggressively.
> 
>   
> http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2018q4/012709
> .html
> 
>   https://launchpadlibrarian.net/405377161/dnsmasq_2.80-1_2.80-1ubuntu1.diff.gz
>   (the commit ID referenced in the changelog there seems or from
>   somewhere else, it's the same patch)
> 
> Cheers,
> 
> 
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> 

--
Petr Menšík
Software Engineer
Red Hat, http://www.redhat.com/
email: pemensik at redhat.com  PGP: 65C6C973





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