Date: Thu, 19 May 2005 12:25:55 -0700 From: Maksim Yevmenkin <maksim.yevmenkin@savvis.net> To: peadar@freebsd.org Cc: freebsd-current@freebsd.org Subject: Re: CURRENT: ifconfig tap0 results in core dump Message-ID: <428CE843.7040705@savvis.net> In-Reply-To: <34cb7c84050519083477639cd5@mail.gmail.com> References: <yq3jekc34sc6.fsf@lagavulin.it.helsinki.fi> <790a9fff0505190809428abb15@mail.gmail.com> <34cb7c84050519083477639cd5@mail.gmail.com>
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Peter Edwards wrote: >>>% ifconfig tap0 >>>tap0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500 >>> inet6 fe80::2bd:9ff:fe7c:100%tap0 prefixlen 64 scopeid 0x5 >>>zsh: segmentation fault (core dumped) ifconfig tap0 >>> >>> >>>I remember that ifconfig didn't dump core when my laptop ran CURRENT >>>from a few months ago. >>> >> >>You'll probably need to build a version of ifconfig with debugging >>symbols. And then provide a backtrace of the core dump. >> >>How soon after killing openvpn, do you use the ifconfig command. It >>might be possible that devfs was in the process of removing tap0, when >>you used the ifconfig command. >> > > Hm. > It looks like the "close" code for if_tap clears out the addresses of > the interface with a pretty blunt-edged "bzero", rather than removing > them in any clean fashion. As a result, ifconfig gets confused over > the address families in the tags it sees on the addresses it > enumerates off the tap interface, and collapses with a corefile. > > if_tap's "close" seems to be trying to do part of what's done in > if_detach, so I split out what I think are the relevant bits from > there and used it in both places. > > Any networking experts care to take a look at the patch? I suspect > there's a whole mess of locking I'm not doing for a start, but I think > it might be an improvement over the current situation. i'm not an expert, but i took a brief look at it, and, it looks fine to me. does this patch fix the ifconfig(8) problem? max
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