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 09:13:21 +1000
Michael Ellerman <mpe at ellerman.id.au> wrote:

> Try just removing the call to btext_unmap() entirely and see how far it goes?
> 
> cheers

Ok, I commented out btext_unmap() in MMU_init() and the freeze just happens before the "Linux version 6.5.0-rc6-PMacG4-dirty [...]"-line:

[    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] setup_kuap:23
[    0.000000] setup_kuap:25
[    0.000000] setup_kuap:30
[    0.000000] setup_kuap:35
[    0.000000] Activating Kernel Userspace Access Protection
[    0.000000] setup_kuap:40
[    0.000000] Activating Kernel Userspace Execution Prevention

I also tried a kernel without KUAP/KUEP getting this:

[    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

Here too the freeze just happens before the line "Linux version 6.5.0-rc6-PMacG4-dirty [...]" in dmesg.

Attached is (warm boot) dmesg without KUAP/KUEP.

Regards,
Erhard
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