Crashes on 5.4R

[Freminlins]

Hello,

I have a machine which I've installed afresh with 5.4R last week. It
is a dual Xeon machine with hyperthreading. Since I've updated it, it
has crashed regularly. So regularly that I have had to remove it from
service.

I built a debugging kernel and from my last crash dump I get the following:

#0  doadump () at pcpu.h:159
159             __asm __volatile("movl %%fs:0,%0" : "=r" (td));

Now, I'm in the fortunate position of not having FreeBSD crash
usually, so I'm not sure what to do next.

Can someone offer some help?

Thanks,
Frem.