Re: TCP crashes kernel

Michael L. Galbraith (
Fri, 27 Feb 1998 07:00:10 +0100 (MET)

On Tue, 24 Feb 1998, William T. Waters wrote:

> I have discovered a problem with what looks like the networking layer of the
> Linux kernel. The following program will consistently crash an intel box.
> It is crippling our efforts to port our software to Linux -- under any sort of
> load whatsoever, machines are rolling over & just dying. Sometimes the
> program will SEGV or get a Bus Error, sometimes we get kernel syslogs, and
> frequently the whole machine will seize up completely.
> Alan Cox has confirmed that this is a problem in 2.0.33, and I just repeated
> it on the latest 2.1.88 kernel as well.
> Is anyone else seeing this error in the "real world"?
> Any help in fixing this would be GREATLY appreciated.
> Bill

Hello Bill, Network Gurus,

I played around with your testprog for several hours yesterday (2.1.88).
The thing works fine here as long as the addresses are resolvable via
my local DNS; whether I use local host addresses or communicate with my
laptop. As soon as I set IP_ADDRESS to a non-resolvable (DNS needs
to contact forwarder and can't because ISDN line not uped), the machine
freezes hard after a brief spurt of net activity. IRQ's are dead, no
blinkenlites, so ktracer can't Oops it.

(Time to try to wedge Ingo's NMI oopser into ktracer I guess :)

Would a tcpdump of the last gasp communication between laptop/desktop
be of any use?

The problem is 100% reproducable.


P.S. was running 'crash' as joe-user.

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