Kernel trap type 0xE

[Eric Gisin]

We have been getting a lot of kernel type 0xE traps
on our Interactive 2.2 system. Under 2.0 the machine
would crash a lot but there were usually no clues as to why.

I looked up interrupt 0xE in the Intel manual and it is a page fault.
Several people have claimed they are hardware related (memory or bus),
but I can't see how this can be the case. You only get this fault
when an address mapping results in a page table entry with the
page-present bit of zero or when page access is denied.
If a hardware problem was causing random page faults,
you would expect some of them to occur in user-mode
resulting in a process being killed with SIGSEGV,
but I haven't seen any of these.
Can anyone explain or speculate how a hardware problem
could be causing page faults?

Two crashes I did debug had a null-pointer dereference in namei(),
one called from open() the other for exece().
Two other crashes occured during reboot in wdrintr().
Could these be software-bug generated faults?

We also had to upgrade our CPU from the SX211 version to SX219
to get 2.2 boot/install to come up. This required removing the
motherboard to get the CPU to seat properly. Not recommend
for non-hardware gurus. Does Interactive acknowledge that
you may have to upgrade your CPU to install 2.2?