[erlang-questions] strange badarith error

[Anthony Shipman]

Today I was getting this occasional error while stress-testing:

23-Jun-2011 18:24:20.290| ERROR fleetDevMgr: device 38: The process for the 
device has exited for reason: {badarith,                                                                           
[{fleetDevImpl,qualFromDevice, 2},                                                                            
{fleetDevImpl, handle_cast, 2},                                                                            
{asn1rt_ber_bin, cindex, 3}]}

where the code in qualFromDevice is

case streamUtils:computeSTEPQuality(Q, true) of
{ok, RSUp, RSDown, RSUpBad, _, Blurb} ->
     ?DEBUG("fleetDevImpl: ~s: quality ~s", [deviceName(), Blurb]),

      T1 = State#state.traffic,
      T2 = T1#voiceTrafficStats{frameErr = (if RSUp == 0 -> 0.0; true -> 
RSUpBad/RSUp end)},

      State#state{
          currTraffic = {RSUp, RSDown},   % totals since the beginning of the 
call
          traffic     = T2,
          trafficChg  = true
          };
_ ->
    State
end

The only arithmetic in here is the division RSUpBad/RSUp and they are 
definitely integers. The DEBUG line is definitely executed.

The code has been compiled with Hipe in R12B4
Erlang (BEAM) emulator version 5.6.4 [source] [async-threads:0] [hipe] 
[kernel-poll:true]

Is it possible I've got bad machine code here?

Why might asn1rt_ber_bin be in the stack trace when it isn't involved in this 
code at all?

-- 
Anthony Shipman                    Mamas don't let your babies 
als@REDACTED                   grow up to be outsourced.