Kernel error, after shutdowning ppp device

["?=sanya G=?koi8-r?Q?"]

Hi, all.
I've installed FC2 and configured ppp connection similar to my old FC1
configuration. It's works well, but when i try to shutdown ppp0 (ifdown ppp0),
pppd starts using 100% of cpu and i get the following errors in /var/log/messages:
kernel: unregister_netdevice: waiting for ppp0 to become free. Usage count = 1
I can't kill pppd as root with kill -9.

Maybe it's a kernel-2.6 bug?
(kernels 2.6.5-1.358, 2.6.6-1.427 and 2.6.7-rc3 from kernel.org)

Any suggestions?

Thanks.