From owner-freebsd-net@FreeBSD.ORG  Thu Oct 20 20:23:28 2005
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Date: Fri, 21 Oct 2005 09:23:27 +1300
From: Andrew Thompson <thompsa@freebsd.org>
To: "Wojciech A. Koszek" <dunstan@freebsd.czest.pl>
Message-ID: <20051020202327.GA53753@heff.fud.org.nz>
References: <20051020202034.GA4556@freebsd.czest.pl>
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Cc: freebsd-net@freebsd.org
Subject: Re: Dependency between interfaces
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On Thu, Oct 20, 2005 at 08:20:34PM +0000, Wojciech A. Koszek wrote:
> Hello,
> 
> Is EVENTHANDLER(9) proper way of notification for standalone driver about
> network interface attach/detach operations? I've met simple problem in
> ef(4), which causes machine freeze in following situation: load NIC driver
> -> load if_ef -> unload NIC driver -> some activity with interface.
> Althought driver of network interface no longer exists, if_ef does not know
> about it and continues it's operation.
> 
> I've seen similar situation for example in ng_fec(4): piece of code needs to
> call some cleanup routines in order to keep pointers in valid state. I think
> this situation is almost the same like this current in if_bridge(4). Just
> repeat situation described above for ef(4), but with if_bridge(4).
> 

if_bridge(4) now hooks into ether_detach to get notified of a vanishing
interface, as of r1.26 (and now in RELENG_6*)

  Use bridge_ifdetach() to notify the bridge that a member has been
  detached.  The bridge can then remove it from its interface list and
  not try to send out via a dead pointer.

Is it still a problem or did you test on a pre r1.26 kernel?

Andrew