kernel panic with greater that 8 GB of memory

[James R. Van Artsalen]

Scott Long wrote:

>>> Bounce buffers with >4GB were indeed broken in 5.3-RELEASE.  I fixed 
>>> them about a week ago in 5-STABLE and 6-CURRENT.  You can work around
>>> the breakage in 5.3-R by setting the following in /boot/loader.conf:
>>>
>>> vm.old_contigmalloc=1
>>
>>
> You should have rev 1.59.2.2 of /sys/i386/i386/busdma_machdep.c


I'm using amd64.  That same change appears to be in 1.57.2.2 on amd64.  
I have that file version.

Unfortunate my system still crashes using more than 4GB of RAM.  The 
symptom is a hard lockup, not a panic.

This usually happens very quickly after NIC initialization begins.  NIC 
bge(4) needs bounce buffers.  My disk controller, twa(4), does not need 
bounce buffers and seems fine in single user mode with no NIC with 8GB.

The system is limited to 4GB of RAM by putting "set hw,physmem=4g" in 
loader.rc rather than making any hardware changes.  The hardware ran 
5.2.1 for several months with 8GB so I think the hardware works.  There 
are two CPUs and two DIMMs for each CPU.