Date: Sun, 24 Nov 1996 00:39:40 -0800 (PST) From: Tom Samplonius <tom@sdf.com> To: Kent Vander Velden <graphix@iastate.edu> Cc: hackers@freefall.freebsd.org Subject: Re: ping and freebsd crashes Message-ID: <Pine.NEB.3.94.961124003102.10075A-100000@misery.sdf.com> In-Reply-To: <9611240526.AA18429@spiff.cc.iastate.edu>
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On Sat, 23 Nov 1996, Kent Vander Velden wrote: > After reading the url that was mentioned earlier about ping I tried to > crash an Irix 5.2 machine. I used OSF/1 v3.2 'ping -q -f -l 200 -s > 5000'. The network appeared to take quite a beating. Sort of related > to wanting to try this was that I have been working on a network packet > analyzer and wanted to see how much of a load this pinging would cause. > The network analyzer runs on a freebsd machine and uses libpcap. The > interesting part of all this is the freebsd machine crashed and in fact > crashed really hard. In the worst case a user's home directory and 50% > of /bin and misc. was removed. I must point out that the freebsd > machine was not being pinged nor was it doing the pinging it was simply > a machine on the network with it's interface running in promiscuous mode. > I also tried tcpdump to make sure that it was not my program that was > causing problems with the same result. Was your analyzer doing disk i/o at the same time? To the affected filesystems? How much memory does the test machine have in it? > There where many > "lnc0: missed packet -- no receive buffer" > and > "lnc0: Framming error" > messages with the killer appearing to be > "panic brelse: free buffer onto another queue?" Have you tried some other kind of ethernet card? It could be driver related. > Perhaps this problems is no longer present. I wish I could tell you > the version of the os that I had but that was lost when I installed the > 961014 snap to reclaim the binaries lost during the crashes. I will try > to find if this problem is present with this snapshot as soon as I am in > a position that I will not lose network connectivity if the machine does > not come back up. > > This would seem like a rather serious problem. Not really. It involves putting the ethernet device in promiscous mode. This is rare and involves root access. It has always been risky, because some hardware doesn't like it. I've seen some NE2000s get stuck in promiscous mode and do all kinds of strange things. > Thanks. > > --- > Kent Vander Velden > graphix@iastate.edu > > Tom
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