Re: KASAN debug kernel fails to boot at early stage when CONFIG_SMP=y is set (kernel 6.5-rc5, PowerMac G4 3,6)
From: Erhard Furtner <hidden>
Date: 2023-09-12 20:10:31
On Tue, 12 Sep 2023 17:39:10 +0000 Christophe Leroy [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Ah ok, maybe your CPU only has 4 BATs and they are all used, following change would tell us.diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c index 850783cfa9c7..bd26767edce7 100644 --- a/arch/powerpc/mm/book3s32/mmu.c +++ b/arch/powerpc/mm/book3s32/mmu.c@@ -86,6 +86,7 @@ int __init find_free_bat(void) if (!(bat[1].batu & 3)) return b; } + pr_err("NO FREE BAT (%d)\n", n); return -1; }Or you have 8 BATs in which case it's an alignment problem, you need to increase CONFIG_DATA_SHIFT to 23, for that you need CONFIG_ADVANCED and CONFIG_DATA_SHIFT_BOOL
Applied all your patches. According to the output my G4 DP seems to have 8 BATs. Now I get the following output on screen before the freeze: printk: bootconsole [udbg0] enabled Total memory = 2048MB; using 4096kB for hash table mapin_ram:125 mmu_mapin_ram:170 0 30000000 1400000 2000000 __mmu_mapin_ram:147 0 1400000 __mmu_mapin_ram:156 1400000 __mmu_mapin_ram:147 1400000 30000000 NO FREE BAT (8) __mmu_mapin_ram:156 20000000 __mapin_ram_chunk:107 20000000 30000000 __mapin_ram_chunk:117 mapin_ram:134 kasan_mmu_init:132 kasan_mmu_init:135 0 kasan_mmu_init:140 ioremap() called early from btext_map+0x64/0xdc. Use early_ioremap() instead Linux version 6.6.0-rc1-PMacG4-dirty (root@T1000) (gcc (Gentoo 12.3.1_p20230526 p2) 12.3.1 20230526, GNU ld (Gentoo 2.40 p7) 2.40.0) #5 SMP Tue Sep 12 16:50:47 CEST 2023 kasan_init_region: c0000000 30000000 f8000000 fe000000 NO FREE BAT (8) kasan_init_region: loop f8000000 fe000000 So I set CONFIG_DATA_SHIFT=23 as suggested but then I only get: printk: bootconsole [udbg0] enabled Total memory = 2048MB; using 4096kB for hash table mapin_ram:125 mmu_mapin_ram:170 0 30000000 1400000 2000000 __mmu_mapin_ram:147 0 1400000 __mmu_mapin_ram:156 1400000 __mmu_mapin_ram:147 1400000 30000000 NO FREE BAT (8) __mmu_mapin_ram:156 20000000 __mapin_ram_chunk:107 20000000 30000000 __mapin_ram_chunk:117 mapin_ram:134 kasan_mmu_init:132 kasan_mmu_init:135 0 kasan_mmu_init:140 With btext_unmap() left in place in init_32.c I only get: printk: bootconsole [udbg0] enabled Total memory = 2048MB; using 4096kB for hash table mapin_ram:125 mmu_mapin_ram:170 0 30000000 1400000 2000000 __mmu_mapin_ram:147 0 1400000 __mmu_mapin_ram:156 1400000 __mmu_mapin_ram:147 1400000 30000000 NO FREE BAT (8) __mmu_mapin_ram:156 20000000 __mapin_ram_chunk:107 20000000 30000000 __mapin_ram_chunk:117 mapin_ram:134 btext_unmap:129 Hope the output sheds at least some light on what's going wrong! Regards, Erhard