kernel since 5.6 do not boot anymore on Apple PowerBook

[Giuseppe Sacco]

Hello,

Il giorno ven, 21/08/2020 alle 16.03 +0200, Christophe Leroy ha
scritto:
[...]
> Thanks.
> 
> The Oops in the video shows that the issue is at 0x1bcac and msr
> value 
> shows that Instruction MMU is disabled. So this corresponds to
> address 
> 0xc001bcac. In the vmlinux you sent me this address is in 
> power_save_ppc32_restore()
> 
> This issue is fixed by 
> https://patchwork.ozlabs.org/project/linuxppc-dev/patch/7bce32ccbab3ba3e3e0f27da6961bf6313df97ed.1581663140.git.christophe.leroy@c-s.fr/
> 
> 
> You also said in a previous mail that your original issue also
> happens 
> when CONFIG_VMAP_STACK is not selected. The above bug being linked
> to 
> CONFIG_VMAP_STACK, maybe it would be easier to bisect with 
> CONFIG_VMAP_STACK unselected.

I rebuilt the same kernel that I would otherwise have skipped because
of the other bug, and it worked, indeed.
I will continue my "bisect quest" unselecting VMAP_STACK in order to
speed up the bisecting.

Thank you very much,
Giuseppe