ruby 2.6.3 died with "divide error" when switching to fbcon

[Helge H. <hel...@ai...>]

Configuration: matrox G550 dualhead, everything compiled-in (fbcon & 
framebuffer) no modules, smp, no preempt.

(Some stuff omitted, but I have a digital photo of it
if it matters.)

The framebuffers came up fine, then I got this:
Console: switching to colour MATROX 160x64 vc:1-16
divide error: 0000 [#1]
CPU:1
EIP: 060:[<c02afccb>] Not tainted
EFLAGS: 00010246
EIP is at cfb_imageblit+0x27b/0x610
eax:00000020 ebx:00000000 ecx: 00000020 edx: 00000000
esi:00000000 edi:00000000 ebp: 00000000 esp: c13dfd84
ds:007b es:007b ss:0068
Process swapper (pid:1 ...
stack: ...
Call trace:
move_buf_aligned
accel_putc
fbcon_putc
hide_softcursor
update_screen
vt_map_display
fbcon_add
cache_alloc_refill
fbcon_event_notify
notifier_call_chain
register_framebuffer
matroxfb_db_regit
matroxfb_db_register
fbcon_add
matroxfb_crtc2_probe
matroxfb_register_driver
matroxfb_crtc2_init
do_initcalls
init_workqueues
init
init
kernel_thread_helper
Code: f7 f7 85 d2 0f 85 ab 01 00 00 85 ed 0f 85 a3 01 00 00 8b 54
<0>Kernel panic: Attempted to kill init!
<0>Rebooting in 300 seconds

I checked out ruby from cvs yesterday, and copied it into
a 2.6.3 source tree.

Helge Hafting