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

Petr Mensik pemensik at redhat.com
Wed Aug 28 18:27:35 BST 2019

Hi Vladislav,

No, I am talking about different issue, commit already released in
latest release. It was introduced by commit [1]. I have no proper fix
for it yet, but revert offending commit.

I think you were mentioning issue is have different reproducer for [2],
TCP no longer listened on interface after recreation. I have working fix
to that too [3], applied already in Fedora. Only feedback so far was
issue with [1], sounds good. Original issue with the same address is
already fixed. But my Thunderbird does not display it well, maybe others
have also issues with it. That is why I started creating pull requests
to myself...

3. https://github.com/InfrastructureServices/dnsmasq/pull/1

On 8/28/19 1:25 PM, Vladislav Grishenko wrote:
> 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,

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

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