8.3 -> 9.1 results in often crashes.

[Pawel Tyll]

Here's more info, including backtrace:

Fatal trap 12: page fault while in kernel mode
cpuid = 3; apic id = 03
fault virtual address   = 0x0
fault code              = supervisor read data, page not present
instruction pointer     = 0x20:0xffffffff80956c73
stack pointer           = 0x28:0xffffff82ddbe3750
frame pointer           = 0x28:0xffffff82ddbe3760
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 12 (irq275: em1:rx 0)
trap number             = 12
panic: page fault
cpuid = 3
KDB: stack backtrace:
#0 0xffffffff80929bb6 at kdb_backtrace+0x66
#1 0xffffffff808f3b1e at panic+0x1ce
#2 0xffffffff80bfde10 at trap_fatal+0x290
#3 0xffffffff80bfe148 at trap_pfault+0x1e8
#4 0xffffffff80bfe74e at trap+0x3be
#5 0xffffffff80be7f7f at calltrap+0x8
#6 0xffffffff80a7c1af at tcp_input+0x65f
#7 0xffffffff80a0db0d at ip_input+0xdd
#8 0xffffffff809b7288 at netisr_dispatch_src+0x218
#9 0xffffffff809ace1d at ether_demux+0x14d
#10 0xffffffff809ad0f4 at ether_nh_input+0x1f4
#11 0xffffffff809b7288 at netisr_dispatch_src+0x218
#12 0xffffffff809acd3f at ether_demux+0x6f
#13 0xffffffff809ad0f4 at ether_nh_input+0x1f4
#14 0xffffffff809b7288 at netisr_dispatch_src+0x218
#15 0xffffffff804b1038 at em_rxeof+0x1c8
#16 0xffffffff804b1414 at em_msix_rx+0x24
#17 0xffffffff808c73bd at intr_event_execute_handlers+0xfd

p.