Re: [Dnsmasq-discuss] dnsmasq 2.86 crash
Hi Simon, On Tue, Oct 19, 2021 at 03:51:28PM +0100, Simon Kelley wrote: > On 15/10/2021 04:45, Eloy Paris wrote: > > Hi Simon, > > > > I am running 2.87test4, which has the commit you mention below. > > > > 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: > > > > > As Petr says, the REFUSED reply is when there are no suitable servers to > forward a query to. > > Based on the previous crash, which is triggered by there being no > configured servers, this is expected. Reading /etc/resolv.conf is > inherently racy - but the code should keep trying in the case that it > finds an empty /etc/resolv.conf to mitigate this. > > You're not setting --no-poll are you? Sorry for the lack of updates... First of all, the crashes are gone with 2.87test4. Second, my apologies but it must have been a late night or early morning when I wrote: -- Oct 14 23:28:14 chapilu dnsmasq[79367]: reading /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! -- Obviously, /etc/resolv.conf and /etc/hosts are different files that serve very different purposes. (I just read "/etc/hosts" as "/etc/resolv.conf" and thought that after sending the SIGHUP, dnsmasq found "4 DNS servers". That is still what may have happened -- I sent SIGHUP, it re-read /etc/resolv.conf, and that is what made it work, but my reading of the filenames was incorrect and I may have confused everyone.) Third, I am running with "log-debug" and I do not see a dump of upstream servers in the log, as Petr mentioned. Perhaps I should instrument the code to see that for my own troubleshooting and understanding of what dnsmasq actually finds when it logs "reading /etc/resolv.conf". I am seeing the new issue happen very often -- the machine goes to sleep and when it comes back it seems like dnsmasq does not have upstream servers to forward requests to, so the virtual machine that relies on dnsmasq for DNS resolution cannot resolve anything. Finally, no, I am not running with --no-poll. dnsmasq is being invoked by libvirtd as: /usr/bin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper and, if it helps, /var/lib/libvirt/dnsmasq/default.conf contains: -- strict-order pid-file=/run/libvirt/network/default.pid except-interface=lo bind-dynamic interface=virbr0 dhcp-range=192.168.122.2,192.168.122.254,255.255.255.0 dhcp-no-override dhcp-authoritative dhcp-lease-max=253 dhcp-hostsfile=/var/lib/libvirt/dnsmasq/default.hostsfile addn-hosts=/var/lib/libvirt/dnsmasq/default.addnhosts log-debug -- Cheers, Eloy Paris.- > > > > 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. > > > > Cheers, > > > > Eloy Paris.- > > > > 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. ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk
Re: [Dnsmasq-discuss] dnsmasq 2.86 crash
On 15/10/2021 04:45, Eloy Paris wrote:
> Hi Simon,
>
> I am running 2.87test4, which has the commit you mention below.
>
> 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:
>
As Petr says, the REFUSED reply is when there are no suitable servers to
forward a query to.
Based on the previous crash, which is triggered by there being no
configured servers, this is expected. Reading /etc/resolv.conf is
inherently racy - but the code should keep trying in the case that it
finds an empty /etc/resolv.conf to mitigate this.
You're not setting --no-poll are you?
Simon.
> 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.
>
> Cheers,
>
> Eloy Paris.-
>
> 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.
>>
>>
>> On 13/10/2021 05:03, Eloy Paris wrote:
>>> Sorry, I forgot the backtrace; here it is:
>>>
>>> (gdb) bt
>>> #0 0x561772564d46 in lookup_domain (domain=0x561772b1d7a0
>>> "enterprise.activity.windows.com", flags=flags@entry=128,
>>> lowout=lowout@entry=0x7ffe8a4b63ac,
>>> highout=highout@entry=0x7ffe8a4b63b0) at domain-match.c:234
>>> #1 0x561772532b1e in forward_query (udpfd=5,
>>> udpaddr=udpaddr@entry=0x7ffe8a4b6500,
>>> dst_addr=dst_addr@entry=0x7ffe8a4b64e0,
>>> dst_iface=dst_iface@entry=13, header=header@entry=0x561772b1fae0,
>>> plen=plen@entry=49, limit=0x561772b1fce0 "", now=1634091453,
>>> forward=0x0, ad_reqd=0, do_bit=0) at forward.c:258
>>> #2 0x56177253387e in receive_query
>>> (listen=listen@entry=0x561772b1f400, now=now@entry=1634091453) at
>>> forward.c:1636
>>> #3 0x561772538b7c in check_dns_listeners (now=now@entry=1634091453) at
>>> dnsmasq.c:1810
>>> #4 0x56177251888b in main (argc=, argv=)
>>> at dnsmasq.c:1237
>>> (gdb)
>>>
>>>
>>> On Tue, Oct 12, 2021 at 10:55:22PM -0400, Eloy Paris wrote:
Hello,
I am experiencing crashes in dnsmasq (2.86). I am able to reproduce it
though I am not sure about the exact sequence of events -- it happens
when I enable/disable my Ethernet NIC and disable/enable my wireless
NIC.
In this use case, dnsmasq provides DNS and DHCP for a virtual machine
(VM) running on KVM. Something like this:
+-- (Ethernet)-+
| |
Internet + Hypervisor (virbr0) --- VM
| |
+--- (Wi-fi)---+
The interfaces I am enabling and disabling are on the hypervisor
("Ethernet" and "Wi-fi" above; virbr0 never goes down).
I guess dnsmasq does not handle gracefully receiving a DNS request from
the VM when the external interfaces of the hypervisor (Ethernet or
wi-fi) go down?
Some details below; happy to provide more information if that's not
enough to get to the bottom of it.
Cheers,
Eloy Paris.-
--
elparis@chapilu[0]:~$ sudo coredumpctl debug dnsmasq
[sudo] Mot de passe de elparis :
PID: 46002 (dnsmasq)
UID: 65534 (nobody)
GID: 65534 (nobody)
Signal: 11 (SEGV)
Timestamp: Tue 2021-10-12 22:17:33 EDT (11min ago)
Command Line: /usr/bin/dnsmasq
--conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro
--dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
Executable: /usr/bin/dnsmasq
Control Group: /system.slice/libvirtd.service
Unit:
Re: [Dnsmasq-discuss] dnsmasq 2.86 crash
Hi,
dnsmasq returns REFUSED in case no forwarders are defined. That means
/etc/resolv.conf is empty and no explicit server= is given either. Is it
possible it failed to catch new nameservers in resolv.conf? It should
report new nameservers into log.
It is also possible to query servers using dig @localhost txt ch
servers.bind.
I have noticed similar behavior yesterday with dnsmasq under
NetworkManager, with dns=dnsmasq. I disabled connection and reenabled,
but dnsmasq were still refusing resolutions. But in this mode it
configures dnsmasq over d-bus. Probably not related. I had to restart
NetworkManager service. Need to analyse that further, I think this might
be bug in NetworkManager, probably different issue.
Cheers,
Petr
On 10/15/21 05:45, Eloy Paris wrote:
> Hi Simon,
>
> I am running 2.87test4, which has the commit you mention below.
>
> 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.
>
> Cheers,
>
> Eloy Paris.-
>
> 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.
>>
>>
>> On 13/10/2021 05:03, Eloy Paris wrote:
>>> Sorry, I forgot the backtrace; here it is:
>>>
>>> (gdb) bt
>>> #0 0x561772564d46 in lookup_domain (domain=0x561772b1d7a0
>>> "enterprise.activity.windows.com", flags=flags@entry=128,
>>> lowout=lowout@entry=0x7ffe8a4b63ac,
>>> highout=highout@entry=0x7ffe8a4b63b0) at domain-match.c:234
>>> #1 0x561772532b1e in forward_query (udpfd=5,
>>> udpaddr=udpaddr@entry=0x7ffe8a4b6500,
>>> dst_addr=dst_addr@entry=0x7ffe8a4b64e0,
>>> dst_iface=dst_iface@entry=13, header=header@entry=0x561772b1fae0,
>>> plen=plen@entry=49, limit=0x561772b1fce0 "", now=1634091453,
>>> forward=0x0, ad_reqd=0, do_bit=0) at forward.c:258
>>> #2 0x56177253387e in receive_query
>>> (listen=listen@entry=0x561772b1f400, now=now@entry=1634091453) at
>>> forward.c:1636
>>> #3 0x561772538b7c in check_dns_listeners (now=now@entry=1634091453) at
>>> dnsmasq.c:1810
>>> #4 0x56177251888b in main (argc=, argv=)
>>> at dnsmasq.c:1237
>>> (gdb)
>>>
>>>
>>> On Tue, Oct 12, 2021 at 10:55:22PM -0400, Eloy Paris wrote:
Hello,
I am experiencing crashes in dnsmasq (2.86). I am able to reproduce it
though I am not sure about the exact sequence of events -- it happens
when I enable/disable my Ethernet NIC and disable/enable my wireless
NIC.
In this use case, dnsmasq provides DNS and DHCP for a virtual machine
(VM) running on KVM. Something like this:
+-- (Ethernet)-+
| |
Internet + Hypervisor (virbr0) --- VM
| |
+--- (Wi-fi)---+
The interfaces I am enabling and disabling are on the hypervisor
("Ethernet" and "Wi-fi" above; virbr0 never goes down).
I guess dnsmasq does not handle gracefully receiving a DNS request from
the VM when the external interfaces of the hypervisor (Ethernet or
wi-fi) go down?
Some details below; happy to provide more information if that's not
enough to get to the bottom of it.
Cheers,
Eloy Paris.-
--
elparis@chapilu[0]:~$ sudo coredumpctl debug dnsmasq
[sudo] Mot de passe de elparis :
PID: 46002 (dnsmasq)
UID: 65534 (nobody)
GID: 65534 (nobody)
Signal: 11 (SEGV)
Timestamp: Tue
Re: [Dnsmasq-discuss] dnsmasq 2.86 crash
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 ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
Re: [Dnsmasq-discuss] dnsmasq 2.86 crash
Hi Simon,
I am running 2.87test4, which has the commit you mention below.
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.
Cheers,
Eloy Paris.-
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.
>
>
> On 13/10/2021 05:03, Eloy Paris wrote:
> > Sorry, I forgot the backtrace; here it is:
> >
> > (gdb) bt
> > #0 0x561772564d46 in lookup_domain (domain=0x561772b1d7a0
> > "enterprise.activity.windows.com", flags=flags@entry=128,
> > lowout=lowout@entry=0x7ffe8a4b63ac,
> > highout=highout@entry=0x7ffe8a4b63b0) at domain-match.c:234
> > #1 0x561772532b1e in forward_query (udpfd=5,
> > udpaddr=udpaddr@entry=0x7ffe8a4b6500,
> > dst_addr=dst_addr@entry=0x7ffe8a4b64e0,
> > dst_iface=dst_iface@entry=13, header=header@entry=0x561772b1fae0,
> > plen=plen@entry=49, limit=0x561772b1fce0 "", now=1634091453,
> > forward=0x0, ad_reqd=0, do_bit=0) at forward.c:258
> > #2 0x56177253387e in receive_query
> > (listen=listen@entry=0x561772b1f400, now=now@entry=1634091453) at
> > forward.c:1636
> > #3 0x561772538b7c in check_dns_listeners (now=now@entry=1634091453) at
> > dnsmasq.c:1810
> > #4 0x56177251888b in main (argc=, argv=)
> > at dnsmasq.c:1237
> > (gdb)
> >
> >
> > On Tue, Oct 12, 2021 at 10:55:22PM -0400, Eloy Paris wrote:
> >> Hello,
> >>
> >> I am experiencing crashes in dnsmasq (2.86). I am able to reproduce it
> >> though I am not sure about the exact sequence of events -- it happens
> >> when I enable/disable my Ethernet NIC and disable/enable my wireless
> >> NIC.
> >>
> >> In this use case, dnsmasq provides DNS and DHCP for a virtual machine
> >> (VM) running on KVM. Something like this:
> >>
> >>+-- (Ethernet)-+
> >>| |
> >> Internet + Hypervisor (virbr0) --- VM
> >>| |
> >>+--- (Wi-fi)---+
> >>
> >> The interfaces I am enabling and disabling are on the hypervisor
> >> ("Ethernet" and "Wi-fi" above; virbr0 never goes down).
> >>
> >> I guess dnsmasq does not handle gracefully receiving a DNS request from
> >> the VM when the external interfaces of the hypervisor (Ethernet or
> >> wi-fi) go down?
> >>
> >> Some details below; happy to provide more information if that's not
> >> enough to get to the bottom of it.
> >>
> >> Cheers,
> >>
> >> Eloy Paris.-
> >>
> >> --
> >>
> >> elparis@chapilu[0]:~$ sudo coredumpctl debug dnsmasq
> >> [sudo] Mot de passe de elparis :
> >>PID: 46002 (dnsmasq)
> >>UID: 65534 (nobody)
> >>GID: 65534 (nobody)
> >> Signal: 11 (SEGV)
> >> Timestamp: Tue 2021-10-12 22:17:33 EDT (11min ago)
> >> Command Line: /usr/bin/dnsmasq
> >> --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro
> >> --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
> >> Executable: /usr/bin/dnsmasq
> >> Control Group: /system.slice/libvirtd.service
> >> Unit: libvirtd.service
> >> Slice: system.slice
> >>Boot ID: a42fe0fbd18649ad8a6951687e2855d8
> >> Machine ID: 3d34409507634591951da9abb51a3942
> >> Hostname: chapilu
> >>Storage:
> >> /var/lib/systemd/coredump/core.dnsmasq.65534.a42fe0fbd18649ad8a6951687e2855d8.46002.163409145300.zst
> >> (present)
> >> Disk Size: 204.6K
> >>Message: Process 46002 (dnsmasq) of user 65534 dumped core.
> >>
> >> Found module linux-vdso.so.1 with build-id:
> >>
Re: [Dnsmasq-discuss] dnsmasq 2.86 crash
On Wed, Oct 13, 2021 at 09:45:30PM -0400, Eloy Paris wrote: > On Wed, Oct 13, 2021 at 09:44:56AM +0100, Simon Kelley wrote: > > On 13/10/2021 05:03, Eloy Paris wrote: > > > Sorry, I forgot the backtrace; here it is: > > > > > > (gdb) bt > > > #0 0x561772564d46 in lookup_domain (domain=0x561772b1d7a0 > > > "enterprise.activity.windows.com", flags=flags@entry=128, > > > lowout=lowout@entry=0x7ffe8a4b63ac, > > > highout=highout@entry=0x7ffe8a4b63b0) at domain-match.c:234 > > > #1 0x561772532b1e in forward_query (udpfd=5, > > > udpaddr=udpaddr@entry=0x7ffe8a4b6500, > > > dst_addr=dst_addr@entry=0x7ffe8a4b64e0, > > > dst_iface=dst_iface@entry=13, header=header@entry=0x561772b1fae0, > > > plen=plen@entry=49, limit=0x561772b1fce0 "", now=1634091453, > > > forward=0x0, ad_reqd=0, do_bit=0) at forward.c:258 > > > #2 0x56177253387e in receive_query > > > (listen=listen@entry=0x561772b1f400, now=now@entry=1634091453) at > > > forward.c:1636 > > > #3 0x561772538b7c in check_dns_listeners (now=now@entry=1634091453) > > > at dnsmasq.c:1810 > > > #4 0x56177251888b in main (argc=, argv= > > out>) at dnsmasq.c:1237 > > > (gdb) > > > > > 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, Hello Mailinglist, > Glad to hear it might be a known issue. > I'll test that patch and report back. Do know that patch is already in git repository. So no need reason to worry about how to apply it. I look forward to the report back. This email for preventing another self reply. > Cheers, > Eloy Paris.- Groeten Geert Stappers -- Silence is hard to parse ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
Re: [Dnsmasq-discuss] dnsmasq 2.86 crash
Hi Simon,
Glad to hear it might be a known issue. I'll test that patch and report
back.
Cheers,
Eloy Paris.-
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.
>
>
> On 13/10/2021 05:03, Eloy Paris wrote:
> > Sorry, I forgot the backtrace; here it is:
> >
> > (gdb) bt
> > #0 0x561772564d46 in lookup_domain (domain=0x561772b1d7a0
> > "enterprise.activity.windows.com", flags=flags@entry=128,
> > lowout=lowout@entry=0x7ffe8a4b63ac,
> > highout=highout@entry=0x7ffe8a4b63b0) at domain-match.c:234
> > #1 0x561772532b1e in forward_query (udpfd=5,
> > udpaddr=udpaddr@entry=0x7ffe8a4b6500,
> > dst_addr=dst_addr@entry=0x7ffe8a4b64e0,
> > dst_iface=dst_iface@entry=13, header=header@entry=0x561772b1fae0,
> > plen=plen@entry=49, limit=0x561772b1fce0 "", now=1634091453,
> > forward=0x0, ad_reqd=0, do_bit=0) at forward.c:258
> > #2 0x56177253387e in receive_query
> > (listen=listen@entry=0x561772b1f400, now=now@entry=1634091453) at
> > forward.c:1636
> > #3 0x561772538b7c in check_dns_listeners (now=now@entry=1634091453) at
> > dnsmasq.c:1810
> > #4 0x56177251888b in main (argc=, argv=)
> > at dnsmasq.c:1237
> > (gdb)
> >
> >
> > On Tue, Oct 12, 2021 at 10:55:22PM -0400, Eloy Paris wrote:
> >> Hello,
> >>
> >> I am experiencing crashes in dnsmasq (2.86). I am able to reproduce it
> >> though I am not sure about the exact sequence of events -- it happens
> >> when I enable/disable my Ethernet NIC and disable/enable my wireless
> >> NIC.
> >>
> >> In this use case, dnsmasq provides DNS and DHCP for a virtual machine
> >> (VM) running on KVM. Something like this:
> >>
> >>+-- (Ethernet)-+
> >>| |
> >> Internet + Hypervisor (virbr0) --- VM
> >>| |
> >>+--- (Wi-fi)---+
> >>
> >> The interfaces I am enabling and disabling are on the hypervisor
> >> ("Ethernet" and "Wi-fi" above; virbr0 never goes down).
> >>
> >> I guess dnsmasq does not handle gracefully receiving a DNS request from
> >> the VM when the external interfaces of the hypervisor (Ethernet or
> >> wi-fi) go down?
> >>
> >> Some details below; happy to provide more information if that's not
> >> enough to get to the bottom of it.
> >>
> >> Cheers,
> >>
> >> Eloy Paris.-
> >>
> >> --
> >>
> >> elparis@chapilu[0]:~$ sudo coredumpctl debug dnsmasq
> >> [sudo] Mot de passe de elparis :
> >>PID: 46002 (dnsmasq)
> >>UID: 65534 (nobody)
> >>GID: 65534 (nobody)
> >> Signal: 11 (SEGV)
> >> Timestamp: Tue 2021-10-12 22:17:33 EDT (11min ago)
> >> Command Line: /usr/bin/dnsmasq
> >> --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro
> >> --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
> >> Executable: /usr/bin/dnsmasq
> >> Control Group: /system.slice/libvirtd.service
> >> Unit: libvirtd.service
> >> Slice: system.slice
> >>Boot ID: a42fe0fbd18649ad8a6951687e2855d8
> >> Machine ID: 3d34409507634591951da9abb51a3942
> >> Hostname: chapilu
> >>Storage:
> >> /var/lib/systemd/coredump/core.dnsmasq.65534.a42fe0fbd18649ad8a6951687e2855d8.46002.163409145300.zst
> >> (present)
> >> Disk Size: 204.6K
> >>Message: Process 46002 (dnsmasq) of user 65534 dumped core.
> >>
> >> Found module linux-vdso.so.1 with build-id:
> >> c6d7bcf242640b81aef03f231535fa4c2486c744
> >> Found module libffi.so.7 with build-id:
> >> de60e99f39569d11d09160bbdcd486cedc87d2b6
> >> Found module libp11-kit.so.0 with build-id:
> >> 5314ec746546ada6f442b6fdfae15eab9f6d3cdc
> >> Found module libcrypto.so.1.1 with build-id:
> >> 6d23f0a3f354825868d044684fad31d482cc9210
> >> Found module libdl.so.2 with build-id:
> >> 5abc547e7b0949f89f3c0e21ab0c8331a7440a8a
> >> Found module libcrypt.so.2 with build-id:
> >> 3743451bdaf36f951f926927633fd964813025d0
> >> Found module libnss_systemd.so.2 with build-id:
> >> 22990ff716d182c427e26b7a3cf94048b55b3e75
> >> Found module libnss_files.so.2 with build-id:
> >> 1a36dfc01d3a1010b2ee79766a24a8090a3266d5
> >> Found module libgpg-error.so.0 with build-id:
> >> ba85170c2d9343ea05eea8fa2048c212ff4ef552
> >> Found module libgcrypt.so.20 with build-id:
> >> db45f5d5e0f7af1e77324fea1885f974619ad268
> >> Found module libcap.so.2 with build-id:
> >> c1674f9082fedd415876b9f7d9712269163259b5
> >> Found module liblz4.so.1 with
Re: [Dnsmasq-discuss] dnsmasq 2.86 crash
Hi Simon,
It seems to me every call of cleanup_servers() should call
build_servers_array(). I am confident it HAS TO be called when some
record is freed. It makes sense to rebuild it only if something were
added. I am sure dbus.c got missed by mentioned change. It also calls
cleanup_servers() and it can delete some servers. Which means dbus
controlled resolvers would still crash dnsmasq.
Can we modify cleanup_servers to be responsible for serverarray refresh?
It is already called from each place and it does not make sense to
demand both functions explicitly in each place.
An optimization running build_server_array() only when a server was
added or removed. But no simple tracking of additions is done, so let's
rebuild it just everytime. I doubt server reconfiguration happens so
often. Or does it?
Cheers,
Petr
On 10/13/21 10:44, 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.
>
>
> On 13/10/2021 05:03, Eloy Paris wrote:
>> Sorry, I forgot the backtrace; here it is:
>>
>> (gdb) bt
>> #0 0x561772564d46 in lookup_domain (domain=0x561772b1d7a0
>> "enterprise.activity.windows.com", flags=flags@entry=128,
>> lowout=lowout@entry=0x7ffe8a4b63ac,
>> highout=highout@entry=0x7ffe8a4b63b0) at domain-match.c:234
>> #1 0x561772532b1e in forward_query (udpfd=5,
>> udpaddr=udpaddr@entry=0x7ffe8a4b6500, dst_addr=dst_addr@entry=0x7ffe8a4b64e0,
>> dst_iface=dst_iface@entry=13, header=header@entry=0x561772b1fae0,
>> plen=plen@entry=49, limit=0x561772b1fce0 "", now=1634091453,
>> forward=0x0, ad_reqd=0, do_bit=0) at forward.c:258
>> #2 0x56177253387e in receive_query (listen=listen@entry=0x561772b1f400,
>> now=now@entry=1634091453) at forward.c:1636
>> #3 0x561772538b7c in check_dns_listeners (now=now@entry=1634091453) at
>> dnsmasq.c:1810
>> #4 0x56177251888b in main (argc=, argv=)
>> at dnsmasq.c:1237
>> (gdb)
>>
>>
>> On Tue, Oct 12, 2021 at 10:55:22PM -0400, Eloy Paris wrote:
>>> Hello,
>>>
>>> I am experiencing crashes in dnsmasq (2.86). I am able to reproduce it
>>> though I am not sure about the exact sequence of events -- it happens
>>> when I enable/disable my Ethernet NIC and disable/enable my wireless
>>> NIC.
>>>
>>> In this use case, dnsmasq provides DNS and DHCP for a virtual machine
>>> (VM) running on KVM. Something like this:
>>>
>>>+-- (Ethernet)-+
>>>| |
>>> Internet + Hypervisor (virbr0) --- VM
>>>| |
>>>+--- (Wi-fi)---+
>>>
>>> The interfaces I am enabling and disabling are on the hypervisor
>>> ("Ethernet" and "Wi-fi" above; virbr0 never goes down).
>>>
>>> I guess dnsmasq does not handle gracefully receiving a DNS request from
>>> the VM when the external interfaces of the hypervisor (Ethernet or
>>> wi-fi) go down?
>>>
>>> Some details below; happy to provide more information if that's not
>>> enough to get to the bottom of it.
>>>
>>> Cheers,
>>>
>>> Eloy Paris.-
>>>
>>> --
>>>
>>> elparis@chapilu[0]:~$ sudo coredumpctl debug dnsmasq
>>> [sudo] Mot de passe de elparis :
>>>PID: 46002 (dnsmasq)
>>>UID: 65534 (nobody)
>>>GID: 65534 (nobody)
>>> Signal: 11 (SEGV)
>>> Timestamp: Tue 2021-10-12 22:17:33 EDT (11min ago)
>>> Command Line: /usr/bin/dnsmasq
>>> --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro
>>> --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
>>> Executable: /usr/bin/dnsmasq
>>> Control Group: /system.slice/libvirtd.service
>>> Unit: libvirtd.service
>>> Slice: system.slice
>>>Boot ID: a42fe0fbd18649ad8a6951687e2855d8
>>> Machine ID: 3d34409507634591951da9abb51a3942
>>> Hostname: chapilu
>>>Storage:
>>> /var/lib/systemd/coredump/core.dnsmasq.65534.a42fe0fbd18649ad8a6951687e2855d8.46002.163409145300.zst
>>> (present)
>>> Disk Size: 204.6K
>>>Message: Process 46002 (dnsmasq) of user 65534 dumped core.
>>>
>>> Found module linux-vdso.so.1 with build-id:
>>> c6d7bcf242640b81aef03f231535fa4c2486c744
>>> Found module libffi.so.7 with build-id:
>>> de60e99f39569d11d09160bbdcd486cedc87d2b6
>>> Found module libp11-kit.so.0 with build-id:
>>> 5314ec746546ada6f442b6fdfae15eab9f6d3cdc
>>> Found module libcrypto.so.1.1 with build-id:
>>> 6d23f0a3f354825868d044684fad31d482cc9210
>>> Found module libdl.so.2 with build-id:
>>> 5abc547e7b0949f89f3c0e21ab0c8331a7440a8a
>>> Found module libcrypt.so.2 with build-id:
>>> 3743451bdaf36f951f926927633fd964813025d0
>>> Found module
Re: [Dnsmasq-discuss] dnsmasq 2.86 crash
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.
On 13/10/2021 05:03, Eloy Paris wrote:
> Sorry, I forgot the backtrace; here it is:
>
> (gdb) bt
> #0 0x561772564d46 in lookup_domain (domain=0x561772b1d7a0
> "enterprise.activity.windows.com", flags=flags@entry=128,
> lowout=lowout@entry=0x7ffe8a4b63ac, highout=highout@entry=0x7ffe8a4b63b0)
> at domain-match.c:234
> #1 0x561772532b1e in forward_query (udpfd=5,
> udpaddr=udpaddr@entry=0x7ffe8a4b6500, dst_addr=dst_addr@entry=0x7ffe8a4b64e0,
> dst_iface=dst_iface@entry=13, header=header@entry=0x561772b1fae0,
> plen=plen@entry=49, limit=0x561772b1fce0 "", now=1634091453,
> forward=0x0, ad_reqd=0, do_bit=0) at forward.c:258
> #2 0x56177253387e in receive_query (listen=listen@entry=0x561772b1f400,
> now=now@entry=1634091453) at forward.c:1636
> #3 0x561772538b7c in check_dns_listeners (now=now@entry=1634091453) at
> dnsmasq.c:1810
> #4 0x56177251888b in main (argc=, argv=)
> at dnsmasq.c:1237
> (gdb)
>
>
> On Tue, Oct 12, 2021 at 10:55:22PM -0400, Eloy Paris wrote:
>> Hello,
>>
>> I am experiencing crashes in dnsmasq (2.86). I am able to reproduce it
>> though I am not sure about the exact sequence of events -- it happens
>> when I enable/disable my Ethernet NIC and disable/enable my wireless
>> NIC.
>>
>> In this use case, dnsmasq provides DNS and DHCP for a virtual machine
>> (VM) running on KVM. Something like this:
>>
>>+-- (Ethernet)-+
>>| |
>> Internet + Hypervisor (virbr0) --- VM
>>| |
>>+--- (Wi-fi)---+
>>
>> The interfaces I am enabling and disabling are on the hypervisor
>> ("Ethernet" and "Wi-fi" above; virbr0 never goes down).
>>
>> I guess dnsmasq does not handle gracefully receiving a DNS request from
>> the VM when the external interfaces of the hypervisor (Ethernet or
>> wi-fi) go down?
>>
>> Some details below; happy to provide more information if that's not
>> enough to get to the bottom of it.
>>
>> Cheers,
>>
>> Eloy Paris.-
>>
>> --
>>
>> elparis@chapilu[0]:~$ sudo coredumpctl debug dnsmasq
>> [sudo] Mot de passe de elparis :
>>PID: 46002 (dnsmasq)
>>UID: 65534 (nobody)
>>GID: 65534 (nobody)
>> Signal: 11 (SEGV)
>> Timestamp: Tue 2021-10-12 22:17:33 EDT (11min ago)
>> Command Line: /usr/bin/dnsmasq
>> --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro
>> --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
>> Executable: /usr/bin/dnsmasq
>> Control Group: /system.slice/libvirtd.service
>> Unit: libvirtd.service
>> Slice: system.slice
>>Boot ID: a42fe0fbd18649ad8a6951687e2855d8
>> Machine ID: 3d34409507634591951da9abb51a3942
>> Hostname: chapilu
>>Storage:
>> /var/lib/systemd/coredump/core.dnsmasq.65534.a42fe0fbd18649ad8a6951687e2855d8.46002.163409145300.zst
>> (present)
>> Disk Size: 204.6K
>>Message: Process 46002 (dnsmasq) of user 65534 dumped core.
>>
>> Found module linux-vdso.so.1 with build-id:
>> c6d7bcf242640b81aef03f231535fa4c2486c744
>> Found module libffi.so.7 with build-id:
>> de60e99f39569d11d09160bbdcd486cedc87d2b6
>> Found module libp11-kit.so.0 with build-id:
>> 5314ec746546ada6f442b6fdfae15eab9f6d3cdc
>> Found module libcrypto.so.1.1 with build-id:
>> 6d23f0a3f354825868d044684fad31d482cc9210
>> Found module libdl.so.2 with build-id:
>> 5abc547e7b0949f89f3c0e21ab0c8331a7440a8a
>> Found module libcrypt.so.2 with build-id:
>> 3743451bdaf36f951f926927633fd964813025d0
>> Found module libnss_systemd.so.2 with build-id:
>> 22990ff716d182c427e26b7a3cf94048b55b3e75
>> Found module libnss_files.so.2 with build-id:
>> 1a36dfc01d3a1010b2ee79766a24a8090a3266d5
>> Found module libgpg-error.so.0 with build-id:
>> ba85170c2d9343ea05eea8fa2048c212ff4ef552
>> Found module libgcrypt.so.20 with build-id:
>> db45f5d5e0f7af1e77324fea1885f974619ad268
>> Found module libcap.so.2 with build-id:
>> c1674f9082fedd415876b9f7d9712269163259b5
>> Found module liblz4.so.1 with build-id:
>> e63600ab23b2f6997f42fac2fa56e1f02ce159a1
>> Found module libzstd.so.1 with build-id:
>> 4b10444c1560ebc574af4d5f488b7408b22d450e
>> Found module liblzma.so.5 with build-id:
>> 8b615460aa230708c5183f16bede67aa0437d95e
>> Found module librt.so.1 with build-id:
>> 75484da2d6f1515189eefa076e0a40328834cd16
>> Found module
Re: [Dnsmasq-discuss] dnsmasq 2.86 crash
Sorry, I forgot the backtrace; here it is:
(gdb) bt
#0 0x561772564d46 in lookup_domain (domain=0x561772b1d7a0
"enterprise.activity.windows.com", flags=flags@entry=128,
lowout=lowout@entry=0x7ffe8a4b63ac, highout=highout@entry=0x7ffe8a4b63b0)
at domain-match.c:234
#1 0x561772532b1e in forward_query (udpfd=5,
udpaddr=udpaddr@entry=0x7ffe8a4b6500, dst_addr=dst_addr@entry=0x7ffe8a4b64e0,
dst_iface=dst_iface@entry=13, header=header@entry=0x561772b1fae0,
plen=plen@entry=49, limit=0x561772b1fce0 "", now=1634091453,
forward=0x0, ad_reqd=0, do_bit=0) at forward.c:258
#2 0x56177253387e in receive_query (listen=listen@entry=0x561772b1f400,
now=now@entry=1634091453) at forward.c:1636
#3 0x561772538b7c in check_dns_listeners (now=now@entry=1634091453) at
dnsmasq.c:1810
#4 0x56177251888b in main (argc=, argv=) at
dnsmasq.c:1237
(gdb)
On Tue, Oct 12, 2021 at 10:55:22PM -0400, Eloy Paris wrote:
> Hello,
>
> I am experiencing crashes in dnsmasq (2.86). I am able to reproduce it
> though I am not sure about the exact sequence of events -- it happens
> when I enable/disable my Ethernet NIC and disable/enable my wireless
> NIC.
>
> In this use case, dnsmasq provides DNS and DHCP for a virtual machine
> (VM) running on KVM. Something like this:
>
>+-- (Ethernet)-+
>| |
> Internet + Hypervisor (virbr0) --- VM
>| |
>+--- (Wi-fi)---+
>
> The interfaces I am enabling and disabling are on the hypervisor
> ("Ethernet" and "Wi-fi" above; virbr0 never goes down).
>
> I guess dnsmasq does not handle gracefully receiving a DNS request from
> the VM when the external interfaces of the hypervisor (Ethernet or
> wi-fi) go down?
>
> Some details below; happy to provide more information if that's not
> enough to get to the bottom of it.
>
> Cheers,
>
> Eloy Paris.-
>
> --
>
> elparis@chapilu[0]:~$ sudo coredumpctl debug dnsmasq
> [sudo] Mot de passe de elparis :
>PID: 46002 (dnsmasq)
>UID: 65534 (nobody)
>GID: 65534 (nobody)
> Signal: 11 (SEGV)
> Timestamp: Tue 2021-10-12 22:17:33 EDT (11min ago)
> Command Line: /usr/bin/dnsmasq
> --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro
> --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
> Executable: /usr/bin/dnsmasq
> Control Group: /system.slice/libvirtd.service
> Unit: libvirtd.service
> Slice: system.slice
>Boot ID: a42fe0fbd18649ad8a6951687e2855d8
> Machine ID: 3d34409507634591951da9abb51a3942
> Hostname: chapilu
>Storage:
> /var/lib/systemd/coredump/core.dnsmasq.65534.a42fe0fbd18649ad8a6951687e2855d8.46002.163409145300.zst
> (present)
> Disk Size: 204.6K
>Message: Process 46002 (dnsmasq) of user 65534 dumped core.
>
> Found module linux-vdso.so.1 with build-id:
> c6d7bcf242640b81aef03f231535fa4c2486c744
> Found module libffi.so.7 with build-id:
> de60e99f39569d11d09160bbdcd486cedc87d2b6
> Found module libp11-kit.so.0 with build-id:
> 5314ec746546ada6f442b6fdfae15eab9f6d3cdc
> Found module libcrypto.so.1.1 with build-id:
> 6d23f0a3f354825868d044684fad31d482cc9210
> Found module libdl.so.2 with build-id:
> 5abc547e7b0949f89f3c0e21ab0c8331a7440a8a
> Found module libcrypt.so.2 with build-id:
> 3743451bdaf36f951f926927633fd964813025d0
> Found module libnss_systemd.so.2 with build-id:
> 22990ff716d182c427e26b7a3cf94048b55b3e75
> Found module libnss_files.so.2 with build-id:
> 1a36dfc01d3a1010b2ee79766a24a8090a3266d5
> Found module libgpg-error.so.0 with build-id:
> ba85170c2d9343ea05eea8fa2048c212ff4ef552
> Found module libgcrypt.so.20 with build-id:
> db45f5d5e0f7af1e77324fea1885f974619ad268
> Found module libcap.so.2 with build-id:
> c1674f9082fedd415876b9f7d9712269163259b5
> Found module liblz4.so.1 with build-id:
> e63600ab23b2f6997f42fac2fa56e1f02ce159a1
> Found module libzstd.so.1 with build-id:
> 4b10444c1560ebc574af4d5f488b7408b22d450e
> Found module liblzma.so.5 with build-id:
> 8b615460aa230708c5183f16bede67aa0437d95e
> Found module librt.so.1 with build-id:
> 75484da2d6f1515189eefa076e0a40328834cd16
> Found module ld-linux-x86-64.so.2 with build-id:
> 040cc3dd10461562f177df39e3be2f3704258c3c
> Found module libmnl.so.0 with build-id:
> fdf3a318247060fa3e451d511ebaf23a7396d1dd
> Found module libnfnetlink.so.0 with build-id:
> 273cc877c7b2ff41e88753edda777d7f1c4017ca
> Found module libunistring.so.2 with build-id:
> 015ac6d6bcb60b7d8bea31a80d1941b06e8636ab
> Found module libsystemd.so.0 with build-id:
>
[Dnsmasq-discuss] dnsmasq 2.86 crash
Hello,
I am experiencing crashes in dnsmasq (2.86). I am able to reproduce it
though I am not sure about the exact sequence of events -- it happens
when I enable/disable my Ethernet NIC and disable/enable my wireless
NIC.
In this use case, dnsmasq provides DNS and DHCP for a virtual machine
(VM) running on KVM. Something like this:
+-- (Ethernet)-+
| |
Internet + Hypervisor (virbr0) --- VM
| |
+--- (Wi-fi)---+
The interfaces I am enabling and disabling are on the hypervisor
("Ethernet" and "Wi-fi" above; virbr0 never goes down).
I guess dnsmasq does not handle gracefully receiving a DNS request from
the VM when the external interfaces of the hypervisor (Ethernet or
wi-fi) go down?
Some details below; happy to provide more information if that's not
enough to get to the bottom of it.
Cheers,
Eloy Paris.-
--
elparis@chapilu[0]:~$ sudo coredumpctl debug dnsmasq
[sudo] Mot de passe de elparis :
PID: 46002 (dnsmasq)
UID: 65534 (nobody)
GID: 65534 (nobody)
Signal: 11 (SEGV)
Timestamp: Tue 2021-10-12 22:17:33 EDT (11min ago)
Command Line: /usr/bin/dnsmasq
--conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro
--dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper
Executable: /usr/bin/dnsmasq
Control Group: /system.slice/libvirtd.service
Unit: libvirtd.service
Slice: system.slice
Boot ID: a42fe0fbd18649ad8a6951687e2855d8
Machine ID: 3d34409507634591951da9abb51a3942
Hostname: chapilu
Storage:
/var/lib/systemd/coredump/core.dnsmasq.65534.a42fe0fbd18649ad8a6951687e2855d8.46002.163409145300.zst
(present)
Disk Size: 204.6K
Message: Process 46002 (dnsmasq) of user 65534 dumped core.
Found module linux-vdso.so.1 with build-id:
c6d7bcf242640b81aef03f231535fa4c2486c744
Found module libffi.so.7 with build-id:
de60e99f39569d11d09160bbdcd486cedc87d2b6
Found module libp11-kit.so.0 with build-id:
5314ec746546ada6f442b6fdfae15eab9f6d3cdc
Found module libcrypto.so.1.1 with build-id:
6d23f0a3f354825868d044684fad31d482cc9210
Found module libdl.so.2 with build-id:
5abc547e7b0949f89f3c0e21ab0c8331a7440a8a
Found module libcrypt.so.2 with build-id:
3743451bdaf36f951f926927633fd964813025d0
Found module libnss_systemd.so.2 with build-id:
22990ff716d182c427e26b7a3cf94048b55b3e75
Found module libnss_files.so.2 with build-id:
1a36dfc01d3a1010b2ee79766a24a8090a3266d5
Found module libgpg-error.so.0 with build-id:
ba85170c2d9343ea05eea8fa2048c212ff4ef552
Found module libgcrypt.so.20 with build-id:
db45f5d5e0f7af1e77324fea1885f974619ad268
Found module libcap.so.2 with build-id:
c1674f9082fedd415876b9f7d9712269163259b5
Found module liblz4.so.1 with build-id:
e63600ab23b2f6997f42fac2fa56e1f02ce159a1
Found module libzstd.so.1 with build-id:
4b10444c1560ebc574af4d5f488b7408b22d450e
Found module liblzma.so.5 with build-id:
8b615460aa230708c5183f16bede67aa0437d95e
Found module librt.so.1 with build-id:
75484da2d6f1515189eefa076e0a40328834cd16
Found module ld-linux-x86-64.so.2 with build-id:
040cc3dd10461562f177df39e3be2f3704258c3c
Found module libmnl.so.0 with build-id:
fdf3a318247060fa3e451d511ebaf23a7396d1dd
Found module libnfnetlink.so.0 with build-id:
273cc877c7b2ff41e88753edda777d7f1c4017ca
Found module libunistring.so.2 with build-id:
015ac6d6bcb60b7d8bea31a80d1941b06e8636ab
Found module libsystemd.so.0 with build-id:
f776aaa16b4e2ba7056d01d928e4b2726ffe2b8b
Found module libpthread.so.0 with build-id:
07c8f95b4f3251d08550217ad8a1f31066229996
Found module libc.so.6 with build-id:
4b406737057708c0e4c642345a703c47a61c73dc
Found module libgmp.so.10 with build-id:
e58d34ab389d1b649c24195c2d145e3ff2e58290
Found module libhogweed.so.6 with build-id:
2d70cff7b1841b4d9ca4e8e7726cd4b944c07fdc
Found module libnettle.so.8 with build-id:
9a878e513c02007598fcf1e2e286c2203f13536e
Found module libnetfilter_conntrack.so.3 with build-id:
0ad526380b1a1986a1e471a84d88d5f2a7fedd80
Found module libidn2.so.0 with build-id:
1ce2b50ad9f9821c2c629b521cf5a3c99593d332
Found module libdbus-1.so.3 with build-id:
74f2ab9c60512f3a93c932c3f627564d42e0b11e
Found module dnsmasq with build-id:
17b49d0999133997748526c51d99bf8b932fb79d
Stack trace of thread 46002:
#0 0x561772564d46 lookup_domain (dnsmasq + 0x55d46)
#1 0x561772532b1e forward_query (dnsmasq + 0x23b1e)
