[Intrepid] Intermittent TCP issues with 2.6.27
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Linux |
Fix Released
|
Medium
|
|||
linux (Ubuntu) |
Won't Fix
|
Medium
|
Unassigned |
Bug Description
I am having intermittent TCP issues with 2.6.27 in a KVM guest. Pings, email and many websites work without issue however several sites do not, e.g:
- store.apple.com
- youtube.com
- www.anz.com (https)
- msn messenger
I have narrowed it down specifically to 2.6.27 through the following troubleshooting:
- rebuilt guest as a clean Intrepid amd64 install (current was upgraded from Hardy)
- rebuilt guest as a clean i386 install
- changed guest network device type from virtio to default (rtl8139)
- tried clamping MSS to 1460 and 1420 (PPP MTU is 1492), as well as auto (--clamp-
- clean iptables firewall with just a MASQUERADE rule
- removed tc htb QoS rules
- built a vanilla 2.6.26 kernel with kernel-package (this worked fine)
- disabled various TCP options, such as tcp_sack, tcp_timestamps and tcp_window_scaling
Basically to go from a problematic state with 2.6.27 to having no issues I simply change the default kernel to 2.6.26 or 2.6.24-21 (Hardy kernel) in /boot/grub/menu.lst and reboot, nothing else resolves the issue.
Originally this was thought to be a symptom of bug #264019 but it appears it may be something different. I will attach PCAP and tcpdump outputs to assist with troubleshooting.
Thanks
Changed in linux: | |
importance: | Undecided → Medium |
status: | Incomplete → Triaged |
Changed in linux: | |
status: | Unknown → Confirmed |
Changed in linux: | |
importance: | Unknown → Medium |
Changed in linux: | |
status: | Confirmed → Fix Released |
Hi Dean,
Can you paste the output of 'cat /proc/version_ signature' so we can see the specific 2.6.27-7 kernel version you are running. You also mention you tested a vanilla 2.6.26 kernel. Just curious if you've tested an newer 2.6.28-rc4 vanilla kernel and if this issue exists there? Thanks.