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Date:      Sun, 2 Jun 1996 12:41:17 +0000 ()
From:      Ade Barkah <mbarkah@hemi.com>
To:        dennis@etinc.com (Dennis)
Cc:        hackers@freebsd.org, freebsd-isp@freebsd.org
Subject:   Re: Nasty Routing BUG in 2.1R
Message-ID:  <199606021241.MAA00954@hemi.com>
In-Reply-To: <199606011534.LAA00235@etinc.com> from "Dennis" at Jun 1, 96 11:34:15 am

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Dennis wrote:
> route delete 200.11.1.17
> 
> /* This causes a panic in the function rtfree(). If you dont delete 
> the route then the host address is unreachable (you get an arpresolve 
> error). */

We've hit this bug (or a variation of it) three times in the past 
week (see my previous message to -hackers.) 

Our setup looks as follows:

----------------                  --------------
| FreeBSD 2.1R | <-- Ethernet --> | Cisco .254 |
----------------                  --------------
                                         |     <--- PPP connection
                                   ------------
                                   | PPP/.252 |
                                   ------------

The .252 machine is linked via PPP to the Cisco. It also has its own 
/26 subnet. For some reason, the .252 machine (a Telebit router) 
doesn't respond to ping x.x.x.252, but it does respond to pings to 
IP addresses on its own subnet. Probably a configuration problem at 
the Telebit end.

To crash the FreeBSD system, simply type 'ping x.x.x.252', which 
generates "/kernel: arpresolve: can't allocate llinfo". I think at 
this time it also generates an invalid/incomplete routing entry. 
Sometime later the system tries to purge this entry, and we get 
panic:rtfree.

The bug is quite disturbing since any user can make the system
unstable by simply issuing 'ping x.252'.

So I set a dumpdev for good measure. Unfortunately, when the
machine panicked again, something happened during the subsequent 
savecore which totally messed up the root partition. (Yippe, that
was 4 hours of sweat and panic, trying to patch it back together
with customers complaining.)

Regards,

-Ade
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