On Fri, 11 Aug 2023 06:45:14 +0000
Christophe Leroy <christophe.le...@csgroup.eu> wrote:

> Le 11/08/2023 à 01:48, Erhard Furtner a écrit :
> > I wanted to fire up my PowerMac G4 MDD (Dual CPU) with a KASAN debug build 
> > of kernel 6.5-rc5 for testing purposes. But the kernel fails to boot at a 
> > very early stage. I only get a white screen reading
> > "done
> > found display: /pci@f0000000/ATY,AlteracParent@10/ATY,Alterac_B@1, 
> > opening..."  
> 
> Can you try with CONFIG_PPC_EARLY_DEBUG and see if you get more 
> information on the screen ?

With CONFIG_PPC_EARLY_DEBUG set booting continues and I get two more lines on a 
white screen:

[    0.000000] printk: bootconsole [udbg0] enabled
[    0.000000] Total memory = 2048MB; using 4096kB for hash table

Afterwards the G4 freezes.

By chane I found out another interesting thing: This only happens on cold boots.

If I boot the G4 up with another kernel first and boot the SMP KASAN kernel 
afterwards it just boots up fine too! On further reboots the SMP KASAN kernel 
keeps booting up normally. Until I turn the machine off - and next time I turn 
it on the same SMP KASAN kernel fails booting again as described. Strange...

This behaviour however is reproducible. Tried that procedure 15-20 times just 
to be sure. Hope you can make something out of it.

Attached is a dmesg of a successful SMP KASAM kernel boot attempt when a 
working kernel was booted first.

Regards,
Erhard F.

Attachment: dmesg_65-rc5_g4_04
Description: Binary data

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