[Dnsmasq-discuss] dnsmasq 2.86 crash

[Geert Stappers]

On Thu, Oct 14, 2021 at 11:45:02PM -0400, Eloy Paris wrote:
> On Wed, Oct 13, 2021 at 09:44:56AM +0100, Simon Kelley wrote:
> 
> > Based on the location of the crash, and the circumstances that cause it,
> > my guess is that this will be fixed by
> > 
> > https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=d290630d31f4517ab26392d00753d1397f9a4114
> > 
> > Please could you try that, and get back to us if it doesn't sort the
> > problem?
> > 
> > 
> > Cheers,
> > 
> > Simon.
> > 
> 
> Hi Simon,
> 
} I am running 2.87test4, which has the commit you mentioned.
> 
> I've tested bringing down and up the external interfaces of the machine
> (the ones that dnsmasq uses to reach the recursive DNS servers to
> fulfill DNS requests it receives) and have not been able to reproduce a
> crash anymore.
> 
> However, after bringing down an interface and a few seconds later
> bringing it back up, DNS resolution stops working.
> 
> I see this in the system log right after I re-enable the interface that
> I previously disabled:
> 
> Oct 14 23:28:14 chapilu dnsmasq[79367]: reading /etc/resolv.conf
> 
> and the packet capture shows:
> 
> 23:29:24.737039 IP 192.168.122.165.60261 > 192.168.122.1.53: 18552+ A? google.com. (28)
> 23:29:24.737126 IP 192.168.122.1.53 > 192.168.122.165.60261: 18552 Refused 0/0/0 (28)
> 
> Under what conditions does dnsmasq respond to a resolution request with
> REFUSED; no servers in /etc/resolv.conf?
> 
> I guess there might be a race condition here because I just sent SIGHUP
> to the dnsmasq process and the system log shows this:
> 
> Oct 14 23:38:34 chapilu dnsmasq[79367]: read /etc/hosts - 4 addresses
> 
> and now DNS resolution works again!
> 
> No idea why dnsmasq is automatically detecting one change in
> /etc/resolv.conf,
> and it apparently is one that does not contain any servers.
> 

And what about the crashes?


> Cheers,
> 
> Eloy Paris.-
 

Groeten
Geert Stappers
-- 
Silence is hard to parse