service iptables stop; hangs constantly on red hat 8

["lartc@manchotnetworks.net" <lartc@manchotnetworks.net>]

hi all,

i have an up2date redhat 8 installation with iptables-1.2.8-8.80.2

as required by my setup, i insmod ip_conntrack_ftp and ip_nat_ftp to
handle connection tracking of ftp sessions.

if a connection has been established, and it becomes closed, or if there
is a current ftp session, "service iptables stop" hangs the machine
while trying to remove modules. here's an example, but it does not
necessairly hang on this module --


[root@aztec root]# ps -eaf | grep mod
root      1728  1672 99 14:39 pts/0    00:01:07 modprobe -r ip_nat_ftp
root      1952  1910  0 14:40 pts/1    00:00:00 grep mod

i have the belief that it is comming from ip_conntrack. in any case, i
can make it happen always (i.e. the system hang). processor time goes to
99% and a reboot is necessary.

has anyone else come accross this? is there something to be flushed
prior to removing the modules?

many thanks!

charles