kernel: trap divide error

[Olivier Bonvalet]

Hello,

I use NginX 0.6.32-1 (the Debian sid package, recompiled for Debian 
Etch) in a 64bit environnement (about 25M hits per day, per server).
NginX is used to serve static contents, and send other queries to an 
Apache server.

I have a lot of errors like this in my logs :
Aug 24 01:48:13 fa20 kernel: nginx[10825] trap divide error ip:43bce1 
sp:7fff4cd38160 error:0 in nginx[400000+6c000]
Aug 24 01:48:18 fa20 kernel: nginx[10826] trap divide error ip:43bce1 
sp:7fff4cd38160 error:0 in nginx[400000+6c000]
Aug 24 01:48:48 fa20 kernel: nginx[11046] trap divide error ip:43bce1 
sp:7fff4cd38160 error:0 in nginx[400000+6c000]
Aug 24 01:49:01 fa20 kernel: nginx[11093] trap divide error ip:43bce1 
sp:7fff4cd38160 error:0 in nginx[400000+6c000]

So I would like to know if it is a "kernel problem", an NginX problem, 
or simply a problem in my NginX configuration.

 From logs, errors started when I modify upstream configuration. For now 
I use this :
    upstream clusterweb {
        server 127.0.0.1:81 weight=4 max_fails=0 fail_timeout=10s;
        server 127.0.0.2:82    backup;
    }
    upstream clusterwebtest {
        server 127.0.0.1:81 max_fails=0 fail_timeout=10s;
        server X.X.X.X:81 max_fails=100 fail_timeout=10s;
        server 127.0.0.2:82    backup;
    }

The "clusterwebtest" upstream is used only for test, there is no trafic 
at all on it.

Thanks in advance for your help.
Olivier Bonvalet