[Dnsmasq-discuss] Infinite loop in dnsmasq v2.86?

[John Byrne]

>> 1) I guess you're using DNSSEC, if that correct?

Yes,

>> 2) How difficult is that to reproduce?

It happened twice in the last week. One interesting thing stood out:   all three were to the admanmedia.com <http://admanmedia.com/> domain. The messages from one look like this:

Jan  4 11:20:03 john daemon.info dnsmasq[1078]: query[A] cs.admanmedia.com from 192.168.1.76
Jan  4 11:20:03 john daemon.info dnsmasq[1078]: forwarded cs.admanmedia.com to 8.8.8.8
Jan  4 11:20:03 john daemon.info dnsmasq[1078]: dnssec-query[DS] admanmedia.com to 8.8.8.8
Jan  4 11:20:03 john daemon.info dnsmasq[1078]: query[A] cs.admanmedia.com from 192.168.1.76


Unfortunately, just doing a two digs to the domain does not reproduce the problem. I wondered if it was something having to do with the second request coming too soon and modified dig to send two requests and that didn't help.


>> 3) Could you set --log-queries, maybe with --log-facility set to a file,
>> if that's easier, and send me the log leading up to a lockup?

I've built with debugging symbols and installed entware gdb, but it doesn't seem to be reporting a sensible stack. So I may not get anything useful from gdb when it hangs. However, I did use the flash drive hosting gdb for the dnsmasq log and capture files. If I haven't affected the timing too badly, I should at least get those for you. I'll let you know.

John Byrne


> On Jan 9, 2022, at 2:48 PM, Simon Kelley <simon at thekelleys.org.uk> wrote:
> 
> On 09/01/2022 22:27, Simon Kelley wrote:
>> On 09/01/2022 10:09, Andreas Metzler wrote:
>>> On 2022-01-06 Andreas Metzler <ametzler at bebt.de> wrote:
>>>> On 2022-01-05 Simon Kelley  wrote:
>>>>> On 04/01/2022 17:11, Andreas Metzler wrote:
>>>> [...]
>>>>>> FWIW this looks similar to https://bugs.debian.org/1001576 which
>>> [...]
>>>>> Are you running with the --strict-order config? The backtrace looks, at
>>>>> least superficially, like the bug fixed in
>>> 
>>>>> https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=2561f9fe0eb9c0be1df48da1e2bd3d3feaa138c2
>>> 
>>>>> Whilst John is not setting --strict order, so that doesn't seem to to be
>>>>> relevant in his case.
>>> 
>>>> Hello Simon,
>>> 
>>>> I have not set strict-order. However I have now rebuilt the Debian
>>>> package with the abovementioned patch. Let's see whether the problem
>>>> goes away.
>>> 
>>> Sadly the patch did not fix the issue.
>> 
>> OK.
>> 
>> A few questions, if that's OK.
>> 
>> 1) I guess you're using DNSSEC, if that correct?
>> 2) How difficult is that to reproduce?
>> 3) Could you set --log-queries, maybe with --log-facility set to a file,
>> if that's easier, and send me the log leading up to a lockup?
>> 
>> 
> 
> 
> .. and further, if possible, configure --dumpfile and --dumpmask=0x00ff
> and send me the packet dump too.
> 
> 
> 
>> 
>> Cheers,
>> 
>> Simon.
>> 
>>> 
>>> cu Andreas
>>> 
>>> _______________________________________________
>>> Dnsmasq-discuss mailing list
>>> Dnsmasq-discuss at lists.thekelleys.org.uk
>>> https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
>>> 
>> 
> 
> 
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