Re: dst cache overflow and network freeze

Kjartan Maraas (kmaraas@online.no)
Mon, 20 Dec 1999 16:51:49 +0100


Andi Kleen wrote:
>
> On Mon, Dec 20, 1999 at 01:42:11PM +0100, Kjartan Maraas wrote:
> > Hi.
> >
> > I keep getting network freezes on 2.3.x kernels. I have a pcmcia
> > 3Com 3CXE589DC card and a Dell Latitude. In the logs i get loads of
> > "dst cache overflow" messages. What happens is that any existing
> > connection ie. IRC. will continue to work, but I can't open a
> > web page etc. fetchmail seemed to work though.
> >
> > from the logs:
> >
> > Dec 19 15:16:17 km-lt kernel: dst cache overflow
> > Dec 19 15:16:22 km-lt kernel: dst cache overflow
> > Dec 19 15:16:30 km-lt kernel: NET: 3 messages suppressed.
> >
> > Trying to telnet to a host:
> >
> > telnet: Unable to connect to remote host: No buffer space available
> >
> > The same goes for ssh.
>
> What does arp -na say ?
>

I will check the next time it happens

> The usual cause is somebody running a port scan over the local network from your
> machine. If you really want to do that you can increase the values in
> /proc/sys/net/ipv4/neigh/gc_thresh[123]
>

Wouldn't downing the eth0 interface and/or restarting pcmia/inet/network
stop this? The errors continued after all this.

I am the only user on the machine, and nothing in the logs suggest that
other people are trying to log in. Any other pointers on how to find out
how and why it happens?

> >
> > Also in the logs I see:
> >
> > Dec 16 11:20:43 km-lt kernel: KERNEL: assertion (dst!=NULL)
> > failed at tcp_output.c(96):tcp_advertise_mss
>
> That is harmless.

Ok thanks.

Cheers
Kjartan Maraas
-
To unsubscribe from this list: send the line "unsubscribe linux-net" in
the body of a message to majordomo@vger.rutgers.edu