Bug 209029

Summary: kernel 5.9-rc2 fails to boot on a PowerMac G5 11,2 - BUG: Kernel NULL pointer dereference on read at 0x00000020
Product: Platform Specific/Hardware Reporter: Erhard F. (erhard_f)
Component: PPC-64Assignee: platform_ppc-64
Status: RESOLVED OBSOLETE    
Severity: normal CC: christophe.leroy, zlang
Priority: P1    
Hardware: PPC-64   
OS: Linux   
Kernel Version: 5.9-rc2 Subsystem:
Regression: No Bisected commit-id:
Attachments: kernel .config (kernel 5.9-rc2, PowerMac G5 11,2)
dmesg screenshot

Description Erhard F. 2020-08-24 22:49:47 UTC
Created attachment 292153 [details]
kernel .config (kernel 5.9-rc2, PowerMac G5 11,2)

Transcribed the stacktrace from a screenshot with my camera:

[...]
REGS: c00000047d0d7850 TRAP:   0700 Tainted: G        W          (5.9.0-rc2-PowerMacG5)
MSR:  9000000000029032 <SF,HV,EE,ME,IR,DR,RI>  CR: 44000448  XER: 200fffff
IRQMASK: 0
GPR00: c000000000af853c c00000047d0d7ae0 c000000000d17300 0000000000000001
GPR04: 00001ccccf255000 c00000047b5c92a8 0000000000000001 0000000000000000
GPR08: c000000000000000 0000000000000001 3fffffffffffffff 4000000000000000
GPR12: 0000000024000448 c00000000ffffc80 c00000000000fd78 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: 0000000000c3e000 c000000000c3e307 c000000000d83b90 c000300000030f80
GPR24: c000000000d83c28 0000000000000c00 c00000047b5c74b0 8000000000000105
GPR28: ee1fffffffffffbf c00000047d64f800 00001ccccf255000 00001ccccf255000
NIP [c000000000af8568] .debug_um_pgtable+0x884/0xa20
LR [c000000000af853c] .debug_vm_pgtable+0x858/0xa20
Call Trace:
[c00000047d0d7ae0] [c000000000af853c] .debug_vm_pgtable++0x858/0xa20 (unreliable)
[c00000047d0d7be0] [c00000000000f62c] .do_one_initcall+0x60/0x344
[c00000047d0d7cc0] [c000000000ad8d64] .kerne]_init_freeable+0x3c0/0x3f4
[c00000047d0d7db0] [c00000000000fd88] .kernel_init+0x10/0x130
[c00000047d0d7e20] [c00000000000b9d8] .ret_from_kerne!_thread+0x58/0x60
Instruction dump:
4b53b145 60000000 e8df0000 7f863278 3f80ee1f 639cffff 7b9c07c6 679cffff
639cffbf 7cc6e038 3146ffff 7cca3110 <0b060000> 39000000 38e00000 38c0ffff
irg event stamp: 369
hardirgs last  enabled at (369): [<c0000000000cd624>] .console_unlock+0x650/0x664
hardirgs last disabled at (366): [<c0000000000cd144>] .console_unlock+0x170/0x664
softirgs last  enabled at (0): [<c00000000005ff38>] .copy_process+0x69c/0x1510
softirgs last disabled at (0): [<0000000000000000>] 0x0
---[ end trace 0561544ca9dc6c57 ]---
BUG: Kernel NULL pointer dereference on read at 0x00000020
ata2: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
Faulting instruction address: 0xc000000000033924
Oops: Kernel access of bad area, sig: 11 [#1]
BE PAGE_SIZE=4K MMU=Hash SMP NR_CPUS=4 NUMA PowerMac
Modules linked in:
CPU: 1 PID: 1 Comm: swapper/0 Tainted: G        W         5.9.0-rc2-PowerMacG5 #2
NIP:  c000000000033924 LR: c0000000000338e4 CTR: 0000000000000000
REGS: c00000047d0d77a0 TRAP: 0380 Tainted: G        W          (5.9.0-rc2-PowerMacG5)
MSR:  9000000000009032 <SF,HV,EE,ME,IR,DR,RI> CR: 44000448 XER: 200fffff
IRQMASK: 0
GPR00: c0000000000338e4 c00000047d0d7a30 c000000000d17300 c00000047d0d7aa8
GPR04: 8000000000c3e387 0000000000000001 8000000000c3e387 0000000000000001
GPR08: c000000000000000 0000000000000000 c000000000d83d48 0000000000000000
GPR12: 0000000024000448 c00000000ffffc80 c00000000000fd78 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: 0000000000c3e000 c000000000c3e307 c000000000d83b90 c000300000030f80
GPR24: c000000000d83c28 0000000000000c00 c00000047b5c74b0 8000000000000105
GPR28: c00000047b5c74b0 0000000000000001 8000000000c3e387 c00000047b5c92a8
NIP [c000000000033924] .huge_ptep_set_access_flags+0x70/0x114
LR [c0000000000338e4] .huge_ptep_set_access_flags+0x30/0x114
Call Trace:
[c00000047d0d7a30] [c0000000000338e4] .huge_ptep_set_access_flags+0x30/0x114 (unreliable)
[c00000047d0d7ae0] [c000000000af86b4] .debug_vm_pgtable++0x9d0/0xa20
[c00000047d0d7be0] [c00000000000f62c] .do_one_initcall+0x60/0x344
[c00000047d0d7cc0] [c000000000ad8d64] .kerne]_init_freeable+0x3c0/0x3f4
[c00000047d0d7db0] [c00000000000fd88] .kernel_init+0x10/0x130
[c00000047d0d7e20] [c00000000000b9d8] .ret_from_kerne!_thread+0x58/0x60
Instruction dump:
794a07c6 654affff 7fc94a78 614affbf 7d295038 2c290000 33a9ffff 7fbd4910
4182008c e93c00a0 3d420007 394aca48 <e9290020> 810a0268 e9290028 e9290648
---[ end trace 0561544ca9dc6c58 ]---

note: swapper/0[1] exited with preempt_count 1
ata2.00: ATA-8: WDC WD5000BPKX-22HPJT0, 01.01A01, max UDMA/133
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
ata2.00: 976773168 sectors, multi 0: LBA48 NCQ (depth 0/32)
Rebooting in 120 seconds..
Comment 1 Erhard F. 2020-08-24 22:51:46 UTC
Created attachment 292155 [details]
dmesg screenshot
Comment 2 Erhard F. 2020-08-31 20:09:00 UTC
No change with 5.9-rc3.
Comment 3 Christophe Leroy 2020-09-01 05:04:10 UTC
Did you try without CONFIG_DEBUG_VM_PGTABLE ?

If you want CONFIG_DEBUG_VM_PGTABLE, the following series aims at fixing it for PPC64: https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=197961
Comment 4 Erhard F. 2020-09-02 10:48:51 UTC
(In reply to Christophe Leroy from comment #3)
> Did you try without CONFIG_DEBUG_VM_PGTABLE ?
Without CONFIG_DEBUG_VM_PGTABLE the G5 boots fine. Thanks!
 
> If you want CONFIG_DEBUG_VM_PGTABLE, the following series aims at fixing it
> for PPC64:
> https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=197961
Did not check the series as current ozlabs patches indicate that the CONFIG_DEBUG_VM_PGTABLE option is removed for the time being.
Comment 5 Zorro Lang 2020-09-07 06:18:54 UTC
*** Bug 209181 has been marked as a duplicate of this bug. ***
Comment 6 Erhard F. 2020-11-21 22:06:53 UTC
Current v5.9.x boots fine on this G5.