how can 'iptables -D ...' get EAGAIN?

Hello,

On a server that has a very dynamic set of iptables rules (used for traffic accounting), I occasionally see a 'iptables -D ...' command in the session start or session end scripts return:

iptables: Resource temporarily unavailable

I've checked the source code for any occurance of EAGAIN (which matches this message) but there isn't any.

Can someone explain in which case iptables would get a EAGAIN error?

This is a -D (delete rule) command, not -L, so I don't think that it can be DNS-related, can it?

Thanks in advance for any hint,
Greets,
_Alain_