As always, the first thing you should try is testing the memory of your computer. The problems seems to be caused by trying to call ip_nat_setup_info() on an already confirmed connection, which is known to cause hash corruption.
I have launch memtest86 and, surprise, i have got memory error. I think i have found the faulty module memory (no more memtest86 error when i leave it from my computer).
So i will test some day to see if i got no more crash.
I didn't think about memory because all crash was on netfilter and never with something else.
thanks for all.
