Comment 12 for bug 2045570

Reproducing the bug

root@j-dnsmasq-2045570:~# apt-cache policy dnsmasq
dnsmasq:
  Installed: 2.86-1.1ubuntu0.4
  Candidate: 2.86-1.1ubuntu0.4
  Version table:
 *** 2.86-1.1ubuntu0.4 500
        500 http://br.archive.ubuntu.com/ubuntu jammy-updates/universe amd64 Packages
        100 /var/lib/dpkg/status
     2.86-1.1ubuntu0.3 500
        500 http://br.archive.ubuntu.com/ubuntu jammy-security/universe amd64 Packages
     2.86-1.1 500
        500 http://br.archive.ubuntu.com/ubuntu jammy/universe amd64 Packages

# dig @127.0.0.1 +short linux.com
23.185.0.3

# echo "#nameserver 1.1.1.1" > /etc/resolv.conf
#

Log:
Jan 23 16:57:40 j-dnsmasq-2045570 dnsmasq[2222]: no servers found in /etc/resolv.conf, will retry

root@j-dnsmasq-2045570:~# dig @127.0.0.1 +short ubuntu.com
;; communications error to 127.0.0.1#53: timed out
;; communications error to 127.0.0.1#53: connection refused
;; communications error to 127.0.0.1#53: connection refused
;; no servers could be reached

And the log show a crash:
Jan 23 17:03:12 j-dnsmasq-2045570 dnsmasq[253]: no servers found in /etc/resolv.conf, will retry
Jan 23 17:03:16 j-dnsmasq-2045570 systemd[1]: dnsmasq.service: Main process exited, code=dumped, status=11/SEGV
Jan 23 17:03:16 j-dnsmasq-2045570 systemd[1]: dnsmasq.service: Failed with result 'core-dump'.

(it took about 3 attempts, but it crashed)

With the new package from jammy-proposed:
root@j-dnsmasq-2045570:~# apt-cache policy dnsmasq
dnsmasq:
  Installed: 2.86-1.1ubuntu0.5
  Candidate: 2.86-1.1ubuntu0.5
  Version table:
 *** 2.86-1.1ubuntu0.5 500
        500 http://br.archive.ubuntu.com/ubuntu jammy-proposed/universe amd64 Packages
        100 /var/lib/dpkg/status
     2.86-1.1ubuntu0.4 500
        500 http://br.archive.ubuntu.com/ubuntu jammy-updates/universe amd64 Packages
     2.86-1.1ubuntu0.3 500
        500 http://br.archive.ubuntu.com/ubuntu jammy-security/universe amd64 Packages
     2.86-1.1 500
        500 http://br.archive.ubuntu.com/ubuntu jammy/universe amd64 Packages

When I perform the same test as before, I get an immediate empty result, and no crash, when resolv.conf contains no server:
root@j-dnsmasq-2045570:~# dig @127.0.0.1 +short ubuntu.com
root@j-dnsmasq-2045570:~#

And the previous result, which was cached, is still there:
root@j-dnsmasq-2045570:~# dig @127.0.0.1 +short linux.com
23.185.0.3

Logs remain silent:
Jan 23 17:08:14 j-dnsmasq-2045570 dnsmasq[1350]: no servers found in /etc/resolv.conf, will retry

If I revert resolv.conf to a working content:
root@j-dnsmasq-2045570:~# echo "nameserver 1.1.1.1" > /etc/resolv.conf

The log notices that:
Jan 23 17:57:47 j-dnsmasq-2045570 dnsmasq[7370]: reading /etc/resolv.conf
Jan 23 17:57:47 j-dnsmasq-2045570 dnsmasq[7370]: using nameserver 1.1.1.1#53

And the server resumes working:
root@j-dnsmasq-2045570:~# dig @127.0.0.1 +short ubuntu.com
185.125.190.21
185.125.190.29
185.125.190.20
root@j-dnsmasq-2045570:~# dig @127.0.0.1 +short linux.com
23.185.0.3
root@j-dnsmasq-2045570:~#

Jammy verification succeeded.