Performing verification for Bind9 on Focal.
I first installed 9.16.1-0ubuntu2.6 from -updates to ensure that the
issue is still present.
I checked that I could look up ubuntu.com through the local caching
resolver. From there I started a second VM, and checked I could look up
addresses through the first VM. I then added the 30% packet loss rule
with tc. From there I opened up 11 tabs in gnome-terminal and hit the
first first VM with:
$ for run in {1..10000}; do dig +tcp @192.168.122.21 ubuntu.com & done
https://paste.ubuntu.com/p/sF9SXkWpZK/
We can see that the "TCP high-water" mark kept rising until it reached
150, when I then killed the thundering herd from the second VM. I then
did a DNS lookup, and found that named was not listening to TCP, and the
lookup timed out.
This confirms that 9.16.1-0ubuntu2.6 from -updates is affected.
I then enabled -proposed, and installed bind9 9.16.1-0ubuntu2.7 and
rebooted.
>From there, I can checked I could look up ubuntu.com through the local
caching resolver, and again started the second VM. The second VM could
also look up addresses through the first VM. I again added a 30% packet
loss with tc. I then opened up 11 tabs of gnome-terminal and hit the
first vm with the dig for loop of doom.
Except this time, once I reached the TCP high water mark and killed the
second VM, the number of TCP connections fell back down to 1, and did
not get stuck at a higher number. I did a TCP DNS lookup for ubuntu.com
on the server, and the request was successful and did not time out.
named is listening to TCP connections as it is suppose to.
https://paste.ubuntu.com/p/SzJMzz6xbh/
bind9 9.16.1-0ubuntu2.7 fixes the problem. Happy to mark as verified.
I will also write back in a few days time with feedback from a user, who
is testing this fixed package in production.
** Tags removed: verification-needed verification-needed-focal
** Tags added: verification-done-focal
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1909950
Title:
named: TCP connections sometimes never close due to race in socket
teardown
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/bind9/+bug/1909950/+subscriptions
--
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
