Comment 9 for bug 1980146

I don't have to do anything to reproduce it, just boot the machine and it starts happening:

⏵ sudo strace -p 823

poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=7, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=13, events=POLLIN}], 8, -1) = 1 ([{fd=4, revents=POLLIN}])

recvmsg(4, {msg_name={sa_family=AF_INET, sin_port=htons(33704), sin_addr=inet_addr("127.0.0.1")}, msg_namelen=28 => 16, msg_iov=[{iov_base="4\312\1\0\0\1\0\0\0\0\0\0\0014\19\18\0015\1c\1d\0017\0016\0016\1b"..., iov_len=4096}], msg_iovlen=1, msg_control=[{cmsg_len=28, cmsg_level=SOL_IP, cmsg_type=IP_PKTINFO, cmsg_data={ipi_ifindex=if_nametoindex("lo"), ipi_spec_dst=inet_addr("127.0.0.53"), ipi_addr=inet_addr("127.0.0.53")}}], msg_controllen=32, msg_flags=0}, 0) = 90

ioctl(4, SIOCGIFNAME, {ifr_ifindex=1, ifr_name="lo"}) = 0

sendto(13, "4\312\1\0\0\1\0\0\0\0\0\0\0014\19\18\0015\1c\1d\0017\0016\0016\1b"..., 90, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.53")}, 16) = 90

As mentioned, I think it happens when an address is denied by dnsmasq.