Description of problem: sfq qdisc stops dequeuing packets under load (hangs), causing complete network outage for all packets assigned to the class to which this sfq qdisc belongs. If I replace the sfq's by pfifo's the problem never shows, so, although I am not absolutely sure, I strongly think the problem is situated in sfq. Version-Release number of selected component (if applicable): kernel-2.6.9-1.681_FC3 How reproducible: Under high load, always within half an hour (checked on two different systems with rather different LAN adapters (1 Intel 10/100/100, 1 3com 3c905c-t-xm). Steps to Reproduce: 1. Execute the attached shell script on a router at one side attached to the Internet via a high speed connection (in my case cable, and in the second setup a 2Mbit serial connection), and at the other side a 10/100 Ethernet switch. The $x parameter is supposed to be the name of the interface at the "inside". 2. Surf around on the Internet, download some things, preferrable with multiple flows, on a PC that uses this router to get to the Internet and that make the packets end up in the sfq qdisc on the router. After a while, all connections will drop. Pings to that host won't work anymore if the echo-reply packets are scheduled to the sfq qdisc that hangs (but the other sfq's attached to sibling classes will keep working normally. I checked this by pinging from that router by setting different QoS bits in the echo-request packet (see man ping)). Observations: At the moment sfq decides to stop dequeuing packets 'tc' shows that there are 126 packets enqueued, always. Any new packet is dropped immediately (or replaces a packet in the sfq, don't know how the queuing exactly works). It remains in this situation forever, until the hanging qdisc is deleted (or the root qdisc). Maybe I haven't waited long enough, but I have waited minutes to see if the problem would solve itself.
Created attachment 108721 [details] script to create a QoS infrastructure, exhibits sfq problem
An update has been released for Fedora Core 3 (kernel-2.6.12-1.1372_FC3) which may contain a fix for your problem. Please update to this new kernel, and report whether or not it fixes your problem. If you have updated to Fedora Core 4 since this bug was opened, and the problem still occurs with the latest updates for that release, please change the version field of this bug to 'fc4'. Thank you.
This bug has been automatically closed as part of a mass update. It had been in NEEDINFO state since July 2005. If this bug still exists in current errata kernels, please reopen this bug. There are a large number of inactive bugs in the database, and this is the only way to purge them. Thank you.