Date: Sun, 10 Jan 1999 16:49:44 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: steven@shellnet.co.uk (Steven Fletcher) Cc: freebsd-net@FreeBSD.ORG Subject: Re: IPFW, Dummynet under 2.2.8-RELEASE. Message-ID: <199901101549.QAA17193@labinfo.iet.unipi.it> In-Reply-To: <3699df97.14510975@smtp.shellnet.co.uk> from "Steven Fletcher" at Jan 10, 99 05:24:05 pm
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> >that is) so you need some option NMBCLUSTERS=3Dsome-high-value > >to be safe. > > My kernel already has: > > maxusers 512 > options "NMBCLUSTERS=3D9000" ok... > >Another possible source of problems could be that buffers reference a > >route (descriptor)=20 > > Aha. Could this have anything to do with the errors I'm getting? > > Jan 9 13:11:48 freebsd /kernel: rtfree: 0xf4822a00 not freed (neg > refs) yes this could be a source of problems. There are a couple of places in ip_dummynet.c where i manipulate the rt_refcnt field. I am doing this at splimp() so i don't think i can be a victim of some race condition. Perhaps you can try removing the decrease of the counter in dn_move(), near the lines below: case DN_TO_IP_OUT: { ... - if (tmp_rt) - tmp_rt->rt_refcnt--; /* XXX return a reference count */ could be that it results in some false release of route entries. (remove the lines marked with '-') If this is a fix the system should remain stable. If it is not, then you might see reference counts for such structures increase too much (with netstat -nr, probably the Refs field is what you need) > I searched the mail archives, but found no real result about this. If the problem is htere, dummynet is the only responsible. > However, these errors don't usually happen near the crashes. unfortunately the problem is that if dummynet makes reference counts incorrect, then a route could be silently freed right before it is used, and the actions on the not-existing-anymore rtentry can destroy some other piece of information. let me know if the above fixes problems. cheers luigi To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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