Re: KASAN debug kernel fails to boot at early stage when CONFIG_SMP=y is set (kernel 6.5-rc5, PowerMac G4 3,6)

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Le 15/08/2023 à 22:01, Erhard Furtner a écrit :
> On Tue, 15 Aug 2023 17:25:13 +0000
> Christophe Leroy <christophe.leroy@csgroup.eu> wrote:
> 
>> I just sent a patch with additional pr_info() in order to help locate
>> the issue, please provide output with that patch.
>>
>> Thanks
>> Christophe
> 
> Thanks for your efforts Christophe! With the patch applied I get this output + a blank black line:

Thanks for your tests and your patience.

> 
> [    0.000000] printk: bootconsole [udbg0] enabled
> [    0.000000] Total memory = 2048MB; using 4096kB for hash table
> [    0.000000] mapin_ram:125
> [    0.000000] mmu_mapin_ram:169 0 30000000 1400000 2000000
> [    0.000000] __mmu_mapin_ram:146 0 1400000
> [    0.000000] __mmu_mapin_ram:155 1400000
> [    0.000000] __mmu_mapin_ram:146 1400000 30000000
> [    0.000000] __mmu_mapin_ram:155 20000000
> [    0.000000] __mapin_ram_chunk:107 20000000 30000000
> [    0.000000] __mapin_ram_chunk:117
> [    0.000000] mapin_ram:134
> [    0.000000] btext_unmap:129
> 
> 
> Afterwards the freeze. On a warm boot after booting another kernel the output continues with "[    0.000000] btext_unmap:131" instead of the black line. Full dmesg of a warm boot attached.

Not sure this is the reason of the crash. Just that it disables bootx 
console here and doesn't re-enable any console before the crash.

Could you move the call to btext_unmap() after the call to 
memblock_set_current_limit(lowmem_end_addr); at the end of function 
MMU_init()

And redo the test, still with my patch applied for the additional pr_infos.


Thanks
Christophe

> 
> Regards,
> Erhard