Hello, Some time ago I''ve read somewhere that local traffic in IMQ could hung up the whole system but it was corrected long time ago. So I was very surprised yesterday when it occurred not true. While testing IMQ I''ve observed for some time that - if you tag some local traffic with iptables both in pre- and postrouting - kernel is hunging up. It is happening quite quick with SMP compiled kernel but without SMP is also possible. After setting soft lockups debbuging they are visible. And then I''ve found this strange thing: packets outgoing from lo to any local address are hooked to IMQ queue from PREROUTING (on ingress). I know they are going there from OUTPUT for routing decision and should be delivered to hooks in PREROUTING like IMQ, but they also should not have IMQ flag set at the moment (they will be "tagged" by iptables in the POSTROUTING future!). But for some reasons (probably some shortcut) they do have this flag and IMQ egress queue is not on their way. So I added this short test in imq_nf_hook and my soft lockups are gone. Jarek P. PS: The included patch could be applied after linux-2.6.16-imq2 patch or eg. my yesterday version linux-2.6.17.4-imq0. _______________________________________________ LARTC mailing list LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc
Jarek Poplawski wrote: ...> And then I''ve found this strange thing: packets outgoing from lo > to any local address are hooked to IMQ queue from PREROUTING (on > ingress). I know they are going there from OUTPUT for routing > decision and should be delivered to hooks in PREROUTING like IMQ, > but they also should not have IMQ flag set at the moment (they > will be "tagged" by iptables in the POSTROUTING future!). But for > some reasons (probably some shortcut) they do have this flag and > IMQ egress queue is not on their way.Bad diagnose! There is no shortcut. Only in my testing procedure: I''ve switched off the egress hook, so the IMQ flag traveled from POSTROUTING to PREROUTING not annoyed. I forgot it isn''t the real device. Sorry for misleading.> So I added this short test in imq_nf_hook and my soft lockups > are gone.Nevertheles this method works. I dont''t know why, yet. It exludes one direction of local traffic from queuing but who cares? Jarek P.
Jarek Poplawski wrote:> PS: The included patch could be applied after linux-2.6.16-imq2 > patch or eg. my yesterday version linux-2.6.17.4-imq0.I think this should go/cc to the IMQ list linuximq@yahoogroups.com http://groups.yahoo.com/group/linuximq/ Subscribe by mail and you won''t get asked for a yahoo ID. Andy.
Andy Furniss <lists <at> andyfurniss.entadsl.com> writes:> > Jarek Poplawski wrote: > > > PS: The included patch could be applied after linux-2.6.16-imq2 > > patch or eg. my yesterday version linux-2.6.17.4-imq0. > > I think this should go/cc to the IMQ list > > linuximq <at> yahoogroups.com > > http://groups.yahoo.com/group/linuximq/ > > Subscribe by mail and you won''t get asked for a yahoo ID.Hello, I had this intention from the start but when I havn''t seen any changes on the web site (from 2006-03-25), no activity on the group site for long time and no posibility to read any archives of that group, I thought maybe here would be some more interest. I''ve seen some patches here, so I dared to send mine. The second receiver was Andre Correa (I think he tries to save his address). After your mail I looked at this group site again and, miracuously, I see some activity today, so I''ll take your advice and subscribe. Thanks, Jarek P.