Created attachment 83401 [details] strace output By chance I detected a small regression that seems to be related to some changes in linux 3.6.0: I have ntp-daemon running and usually could print a list of peers and some further sync information with the command "ntpq -p". Since linux 3.6.0 this command times out ("localhost.localdomain: timed out, nothing received ***Request timed out"). As you can see in the attached strace output the program tries to connect to the ipv6 loopback interface and fails with that. If I explicitly use ipv4 (ntpq -4 -p) the command works fine. If I downgrade my kernel to version 3.5.6 there are no timeouts. I don't have any similar problems with other software. One thing to add: I first reported this bug to my distribution (https://bugs.archlinux.org/task/31775) and found at least one person having the same regression. Please be patient with me, as I don't have any insight into the kernel and might be even wrong with my component classification (ipv6). I'd be glad to help though. Just tell me if you need any further information.
Best place to ask if you are not sure is netdev@vger.kernel.org. Give the detail you have here and a pointer to the bug report. A tcpdump may also be useful
Created attachment 83431 [details] tcpdump with -vvv option
A patch has been sent to the mailing list: http://marc.info/?l=linux-netdev&m=135040905619911&w=2 As it solves the issue for me and no one else is claiming problems this report can be closed, I think. Thank you.
Fixed in kernel version 3.6.4.