NICs locking up, "*tcp_sc_h"

Nick Withers nick at
Wed Mar 18 05:33:54 PDT 2009

On Wed, 2009-03-18 at 11:52 +0000, Robert Watson wrote:
> On Sun, 15 Mar 2009, Nick Withers wrote:
> >> I'll need to think a bit about a proper fix for this, but you'll find the 
> >> problem likely goes away if you eliminate all uid/gid/jail rules from your 
> >> firewall.  You could also tweak the syncache logic not to use a retransmit 
> >> timer, which might slightly extend the time it takes for systems to connect 
> >> to your host in the presence of packet loss, but would eliminate this 
> >> transmission path entirely.  We'll need a real and more general fix, 
> >> however, to commit, and I'll look and see what I can come up with.
> >
> > Brilliant, thanks very much. I'll work without uid rules for the time being, 
> > then.
> Could I ask you to file a PR on this problem, btw, with the two traces I 
> singled out as interesting included, then forward me the PR receipt?  That 
> will make the problem easier to keep track of.

Done - Please see newborn kern/132774!

> We're currently pondering ways to fix the problem that don't disturb the 
> stability of the ABI, and may have a workaround patch available shortly that's 
> appropriate for MFC.

Wow! Must admit I'd assumed this one was going to take a while to sort
out, so I'm certainly happy to hear this.

Cheers very much!

> Robert N M Watson
> Computer Laboratory
> University of Cambridge
Nick Withers
email: nick at
Mobile: +61 414 397 446
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 196 bytes
Desc: This is a digitally signed message part
Url :

More information about the freebsd-stable mailing list