[Dnsmasq-discuss] dnsmasq v2.86?

[Andre Heider]

On 10/08/2021 23:11, Simon Kelley wrote:
> On 10/08/2021 14:53, Dominik wrote:
>> Hey Simon,
>>
>> various dnsmasq-2.86 test tags are around and it doesn't look like
>> there are any intermediate bugs around. The Pi-hole beta seems to have
>> attracted at least a few couple of dozen additional testers and nothing
>> seems to have come up here, either.
>>
>> How do you feel about tagging a v2.86 release?
>>
>> Best regards,
>> Dominik
>>
>>
> 
> I've been accumulating patches for a couple of weeks, and started
> working through those tonight. None are very intrusive or controversial.
> Once those are done, I'll tag rc1.

I'm using 2.86test6 on OpenWrt, and I think I've found a bug. Detail's 
are vague so far but ever since I've started DoT with stubby as upstream 
server, dnsmasq every now and then gets into a mode where it stops 
responding to request completely and just sits there using 100% cpu 
power on one core.
I haven't found a way yet to trigger that reliably, but it feels like 
timing/parallel requests.

Does that ring any bells?

Any hints on how to get more relevant info on the situation? Sometimes 
it takes over a day, so verbose logs seem to be out of the question 
(since it's a small router). How to I get a backtrace without gdb?

config created by OpenWrt:
conf-file=/etc/dnsmasq.conf
dhcp-authoritative
domain-needed
no-resolv
localise-queries
enable-ubus=dnsmasq
expand-hosts
bind-dynamic
local-service
quiet-dhcp
edns-packet-max=1280
domain=internal
local=/internal/
server=127.0.0.1#5453
addn-hosts=/tmp/hosts
dhcp-leasefile=/tmp/dhcp.leases
stop-dns-rebind
conf-file=/usr/share/dnsmasq/trust-anchors.conf
dnssec
dhcp-broadcast=tag:needs-broadcast
conf-dir=/tmp/dnsmasq.d
user=dnsmasq
group=dnsmasq
dhcp-ignore-names=tag:dhcp_bogus_hostname
conf-file=/usr/share/dnsmasq/dhcpbogushostname.conf
bogus-priv
conf-file=/usr/share/dnsmasq/rfc6761.conf
no-dhcp-interface=pppoe-wan
dhcp-range=set:lan,192.168.0.200,192.168.0.254,255.255.255.0,12h

stubby config created by OpenWrt:
resolution_type: GETDNS_RESOLUTION_STUB
round_robin_upstreams: 1
appdata_dir: "/var/lib/stubby"
trust_anchors_backoff_time: 2500
tls_authentication: GETDNS_AUTHENTICATION_REQUIRED
tls_query_padding_blocksize: 128
edns_client_subnet_private: 1
idle_timeout: 10000
listen_addresses:
   - 127.0.0.1 at 5453
dns_transport_list:
   - GETDNS_TRANSPORT_TLS
upstream_recursive_servers:
   - address_data: 5.1.66.255
     tls_auth_name: "dot.ffmuc.net"
   - address_data: 185.150.99.255
     tls_auth_name: "dot.ffmuc.net"
   - address_data: 185.95.218.42
     tls_auth_name: "dns.digitale-gesellschaft.ch"
   - address_data: 185.95.218.43
     tls_auth_name: "dns.digitale-gesellschaft.ch"