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

[Erhard Furtner]

On Fri, 18 Aug 2023 15:47:38 +0000
Christophe Leroy <christophe.leroy at csgroup.eu> wrote:

> I'm wondering if the problem is just linked to the kernel being built 
> with CONFIG_SMP or if it is the actual startup of a secondary CPU that 
> cause the freeze.
> 
> Please leave the btext_unmap() in place because I think it is important 
> to keep it, and start the kernel with the following parameter:
> 
> nr_cpus=1

With btext_unmap() back and place and nr_cpus=1 set the freeze still happens after the 1st btext_unmap:129 on cold boots:

[    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] kasan_mmu_init:129
[    0.000000] kasan_mmu_init:132 0
[    0.000000] kasan_mmu_init:137
[    0.000000] btext_unmap:129

Attached is warm boot dmesg with nr_cpus=1 set.

Regards,
Erhard
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