Subject: Re: [mainline] [linux-next] [6.8-rc1] [FC] [DLPAR] OOps kernel crash after performing dlpar remove test

From: Tasmiya Nalatwad <[email-masked]>
Date: Fri, 2 Feb 2024 12:41:53 +0530

Greetings,

I have tried reverting some latest commits and tested the issue. I see
reverting below commit hits to some other problem which was reported
earlier and the patch for fixing that issue is under review

1. Reverted commit :

      commit 17de3f5fdd35676b0e3d41c7c9bf4e3032eb3673
      iommu: Retire bus ops

2. Below are the traces of other issue that was seen after reverting
above commit, And below is the patch which fixes this issue is that is 
under review

Patch :
https://www.mail-archive.com/[email-masked]/msg225210.html

--- Traces ---

[  981.124047] Kernel attempted to read user page (30) - exploit
attempt? (uid: 0)
[  981.124053] BUG: Kernel NULL pointer dereference on read at 0x00000030
[  981.124056] Faulting instruction address: 0xc000000000689864
[  981.124060] Oops: Kernel access of bad area, sig: 11 [#1]
[  981.124063] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=8192 NUMA pSeries
[  981.124067] Modules linked in: sit tunnel4 ip_tunnel rpadlpar_io
rpaphp xsk_diag nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib
nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct
nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 bonding
tls ip_set rfkill nf_tables libcrc32c nfnetlink pseries_rng vmx_crypto
binfmt_misc ext4 mbcache jbd2 dm_service_time sd_mod t10_pi
crc64_rocksoft crc64 sg ibmvfc scsi_transport_fc ibmveth mlx5_core mlxfw
psample dm_multipath dm_mirror dm_region_hash dm_log dm_mod fuse
[  981.124111] CPU: 24 PID: 78294 Comm: drmgr Kdump: loaded Not tainted
6.5.0-rc6-next-20230817-auto #1
[  981.124115] Hardware name: IBM,9080-HEX POWER10 (raw) 0x800200
0xf000006 of:IBM,FW1030.30 (NH1030_062) hv:phyp pSeries
[  981.124118] NIP:  c000000000689864 LR: c0000000009bd05c CTR:
c00000000005fb90
[  981.124121] REGS: c0000000a878b1e0 TRAP: 0300   Not tainted
(6.5.0-rc6-next-20230817-auto)
[  981.124125] MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR:
44822422  XER: 20040006
[  981.124132] CFAR: c0000000009bd058 DAR: 0000000000000030 DSISR:
40000000 IRQMASK: 0
[  981.124132] GPR00: c0000000009bd05c c0000000a878b480 c000000001451400
0000000000000000
[  981.124132] GPR04: c00000000128d510 0000000000000000 c00000000eeccf50
c0000000a878b420
[  981.124132] GPR08: 0000000000000001 c00000000eed76e0 c000000002c24c28
0000000000000220
[  981.124132] GPR12: c00000000005fb90 c000001837969300 0000000000000000
0000000000000000
[  981.124132] GPR16: 0000000000000000 0000000000000000 0000000000000000
0000000000000000
[  981.124132] GPR20: c00000000125cef0 0000000000000000 c00000000125cf08
c000000002bce500
[  981.124132] GPR24: c0000000573e90c0 fffffffffffff000 c0000000573e93c0
c0000000a877d2a0
[  981.124132] GPR28: c00000000128d510 c00000000eeccf50 c0000000a877d2a0
c0000000573e90c0
[  981.124171] NIP [c000000000689864] sysfs_add_link_to_group+0x34/0x90
[  981.124178] LR [c0000000009bd05c] iommu_device_link+0x5c/0x110
[  981.124184] Call Trace:
[  981.124186] [c0000000a878b480] [c00000000048d630]
kmalloc_trace+0x50/0x140 (unreliable)
[  981.124193] [c0000000a878b4c0] [c0000000009bd05c]
iommu_device_link+0x5c/0x110
[  981.124198] [c0000000a878b500] [c0000000009ba050]
__iommu_probe_device+0x250/0x5c0
[  981.124203] [c0000000a878b570] [c0000000009ba9e0]
iommu_probe_device_locked+0x30/0x90
[  981.124207] [c0000000a878b5a0] [c0000000009baa80]
iommu_probe_device+0x40/0x70
[  981.124212] [c0000000a878b5d0] [c0000000009baaf0]
iommu_bus_notifier+0x40/0x80
[  981.124217] [c0000000a878b5f0] [c00000000019aad0]
notifier_call_chain+0xc0/0x1b0
[  981.124221] [c0000000a878b650] [c00000000019b604]
blocking_notifier_call_chain+0x64/0xa0
[  981.124226] [c0000000a878b690] [c0000000009cd870] bus_notify+0x50/0x80
[  981.124230] [c0000000a878b6d0] [c0000000009c8f04] device_add+0x744/0x9b0
[  981.124235] [c0000000a878b790] [c00000000089f2ec]
pci_device_add+0x2fc/0x880
[  981.124240] [c0000000a878b840] [c00000000007ef90]
of_create_pci_dev+0x390/0xa10
[  981.124245] [c0000000a878b920] [c00000000007f858]
__of_scan_bus+0x248/0x320
[  981.124249] [c0000000a878ba00] [c00000000007c1f0]
pcibios_scan_phb+0x2d0/0x3c0
[  981.124254] [c0000000a878bad0] [c000000000107f08]
init_phb_dynamic+0xb8/0x110
[  981.124259] [c0000000a878bb40] [c008000002cc03b4]
dlpar_add_slot+0x18c/0x380 [rpadlpar_io]
[  981.124265] [c0000000a878bbe0] [c008000002cc0bec]
add_slot_store+0xa4/0x150 [rpadlpar_io]
[  981.124270] [c0000000a878bc70] [c000000000f2f800]
kobj_attr_store+0x30/0x50
[  981.124274] [c0000000a878bc90] [c000000000687368]
sysfs_kf_write+0x68/0x80
[  981.124278] [c0000000a878bcb0] [c000000000685d3c]
kernfs_fop_write_iter+0x1cc/0x280
[  981.124283] [c0000000a878bd00] [c0000000005909c8] vfs_write+0x358/0x4b0
[  981.124288] [c0000000a878bdc0] [c000000000590cfc] ksys_write+0x7c/0x140
[  981.124293] [c0000000a878be10] [c000000000036554]
system_call_exception+0x134/0x330
[  981.124298] [c0000000a878be50] [c00000000000d6a0]
system_call_common+0x160/0x2e4
[  981.124303] --- interrupt: c00 at 0x200013f21594
[  981.124306] NIP:  0000200013f21594 LR: 0000200013e97bf4 CTR:
0000000000000000
[  981.124309] REGS: c0000000a878be80 TRAP: 0c00   Not tainted
(6.5.0-rc6-next-20230817-auto)
[  981.124312] MSR:  800000000280f033
<SF,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE>  CR: 22000282  XER: 00000000
[  981.124321] IRQMASK: 0
[  981.124321] GPR00: 0000000000000004 00007ffff3a55c70 0000200014007300
0000000000000007
[  981.124321] GPR04: 000000013aff5750 0000000000000008 fffffffffbad2c80
000000013afd02a0
[  981.124321] GPR08: 0000000000000001 0000000000000000 0000000000000000
0000000000000000
[  981.124321] GPR12: 0000000000000000 0000200013b7bc30 0000000000000000
0000000000000000
[  981.124321] GPR16: 0000000000000000 0000000000000000 0000000000000000
0000000000000000
[  981.124321] GPR20: 0000000000000000 0000000000000000 0000000000000000
0000000000000000
[  981.124321] GPR24: 000000010ef61668 0000000000000000 0000000000000008
000000013aff5750
[  981.124321] GPR28: 0000000000000008 000000013afd02a0 000000013aff5750
0000000000000008
[  981.124356] NIP [0000200013f21594] 0x200013f21594
[  981.124358] LR [0000200013e97bf4] 0x200013e97bf4
[  981.124361] --- interrupt: c00
[  981.124362] Code: 38427bd0 7c0802a6 60000000 7c0802a6 fba1ffe8
fbc1fff0 fbe1fff8 7cbf2b78 38a00000 7cdd3378 f8010010 f821ffc1
<e8630030> 4bff95d1 60000000 7c7e1b79
[  981.124374] ---[ end trace 0000000000000000 ]---

Thanks and Regards

On 1/31/24 16:18, Robin Murphy wrote:
> On 2024-01-31 9:19 am, Tasmiya Nalatwad wrote:
>> Greetings,
>>
>> [mainline] [linux-next] [6.8-rc1] [DLPAR] OOps kernel crash after 
>> performing dlpar remove test
>>
>> --- Traces ---
>>
>> [58563.146236] BUG: Unable to handle kernel data access at 
>> 0x6b6b6b6b6b6b6b83
>> [58563.146242] Faulting instruction address: 0xc0000000009c0e60
>> [58563.146248] Oops: Kernel access of bad area, sig: 11 [#1]
>> [58563.146252] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=8192 NUMA pSeries
>> [58563.146258] Modules linked in: isofs cdrom dm_snapshot dm_bufio 
>> dm_round_robin dm_queue_length exfat vfat fat btrfs blake2b_generic 
>> xor raid6_pq zstd_compress loop xfs libcrc32c raid0 nvram rpadlpar_io 
>> rpaphp nfnetlink xsk_diag bonding tls rfkill sunrpc dm_service_time 
>> dm_multipath dm_mod pseries_rng vmx_crypto binfmt_misc ext4 mbcache 
>> jbd2 sd_mod sg ibmvscsi scsi_transport_srp ibmveth lpfc nvmet_fc 
>> nvmet nvme_fc nvme_fabrics nvme_core t10_pi crc64_rocksoft crc64 
>> scsi_transport_fc fuse
>> [58563.146326] CPU: 0 PID: 1071247 Comm: drmgr Kdump: loaded Not 
>> tainted 6.8.0-rc1-auto-gecb1b8288dc7 #1
>> [58563.146332] Hardware name: IBM,9009-42A POWER9 (raw) 0x4e0202 
>> 0xf000005 of:IBM,FW950.A0 (VL950_141) hv:phyp pSeries
>> [58563.146337] NIP:  c0000000009c0e60 LR: c0000000009c0e28 CTR: 
>> c0000000009c1584
>> [58563.146342] REGS: c00000007960f260 TRAP: 0380   Not tainted 
>> (6.8.0-rc1-auto-gecb1b8288dc7)
>> [58563.146347] MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 
>> 24822424  XER: 20040006
>> [58563.146360] CFAR: c0000000009c0e74 IRQMASK: 0
>> [58563.146360] GPR00: c0000000009c0e28 c00000007960f500 
>> c000000001482600 c000000003050540
>> [58563.146360] GPR04: 0000000000000000 c00000089a6870c0 
>> 0000000000000001 fffffffffffe0000
>> [58563.146360] GPR08: c000000002bac020 6b6b6b6b6b6b6b6b 
>> 6b6b6b6b6b6b6b6b 0000000000000220
>> [58563.146360] GPR12: 0000000000002000 c000000003080000 
>> 0000000000000000 0000000000000000
>> [58563.146360] GPR16: 0000000000000000 0000000000000000 
>> 0000000000000000 0000000000000001
>> [58563.146360] GPR20: c000000001281478 0000000000000000 
>> c000000001281490 c000000002bfed80
>> [58563.146360] GPR24: c00000089a6870c0 0000000000000000 
>> 0000000000000000 c000000002b9ffb8
>> [58563.146360] GPR28: 0000000000000000 c000000002bac0e8 
>> 0000000000000000 0000000000000000
>> [58563.146421] NIP [c0000000009c0e60] iommu_ops_from_fwnode+0x68/0x118
>> [58563.146430] LR [c0000000009c0e28] iommu_ops_from_fwnode+0x30/0x118
>
> This implies that iommu_device_list has become corrupted. Looks like 
> spapr_tce_setup_phb_iommus_initcall() registers an iommu_device which 
> pcibios_free_controller() could free if a PCI controller is removed, 
> but there's no path anywhere to ever unregister any of those IOMMUs. 
> Presumably this also means that is a PCI controller is dynamically 
> added after init, its IOMMU won't be set up properly either.
>
> Thanks,
> Robin.
>
>> [58563.146437] Call Trace:
>> [58563.146439] [c00000007960f500] [c00000007960f560] 
>> 0xc00000007960f560 (unreliable)
>> [58563.146446] [c00000007960f530] [c0000000009c0fd0] 
>> __iommu_probe_device+0xc0/0x5c0
>> [58563.146454] [c00000007960f5a0] [c0000000009c151c] 
>> iommu_probe_device+0x4c/0xb4
>> [58563.146462] [c00000007960f5e0] [c0000000009c15d0] 
>> iommu_bus_notifier+0x4c/0x8c
>> [58563.146469] [c00000007960f600] [c00000000019e3d0] 
>> notifier_call_chain+0xb8/0x1a0
>> [58563.146476] [c00000007960f660] [c00000000019eea0] 
>> blocking_notifier_call_chain+0x64/0x94
>> [58563.146483] [c00000007960f6a0] [c0000000009d3c5c] 
>> bus_notify+0x50/0x7c
>> [58563.146491] [c00000007960f6e0] [c0000000009cfba4] 
>> device_add+0x774/0x9bc
>> [58563.146498] [c00000007960f7a0] [c0000000008abe9c] 
>> pci_device_add+0x2f4/0x864
>> [58563.146506] [c00000007960f850] [c00000000007d5a0] 
>> of_create_pci_dev+0x390/0xa08
>> [58563.146514] [c00000007960f930] [c00000000007de68] 
>> __of_scan_bus+0x250/0x328
>> [58563.146520] [c00000007960fa10] [c00000000007a680] 
>> pcibios_scan_phb+0x274/0x3c0
>> [58563.146527] [c00000007960fae0] [c000000000105d58] 
>> init_phb_dynamic+0xb8/0x110
>> [58563.146535] [c00000007960fb50] [c0080000217b0380] 
>> dlpar_add_slot+0x170/0x3b4 [rpadlpar_io]
>> [58563.146544] [c00000007960fbf0] [c0080000217b0ca0] 
>> add_slot_store+0xa4/0x140 [rpadlpar_io]
>> [58563.146551] [c00000007960fc80] [c000000000f3dbec] 
>> kobj_attr_store+0x30/0x4c
>> [58563.146559] [c00000007960fca0] [c0000000006931fc] 
>> sysfs_kf_write+0x68/0x7c
>> [58563.146566] [c00000007960fcc0] [c000000000691b2c] 
>> kernfs_fop_write_iter+0x1c8/0x278
>> [58563.146573] [c00000007960fd10] [c000000000599f54] 
>> vfs_write+0x340/0x4cc
>> [58563.146580] [c00000007960fdc0] [c00000000059a2bc] 
>> ksys_write+0x7c/0x140
>> [58563.146587] [c00000007960fe10] [c000000000035d74] 
>> system_call_exception+0x134/0x330
>> [58563.146595] [c00000007960fe50] [c00000000000d6a0] 
>> system_call_common+0x160/0x2e4
>> [58563.146602] --- interrupt: c00 at 0x200004470cb4
>> [58563.146606] NIP:  0000200004470cb4 LR: 00002000043e7d04 CTR: 
>> 0000000000000000
>> [58563.146611] REGS: c00000007960fe80 TRAP: 0c00   Not tainted 
>> (6.8.0-rc1-auto-gecb1b8288dc7)
>> [58563.146616] MSR:  800000000280f033 
>> <SF,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE>  CR: 24000282  XER: 00000000
>> [58563.146632] IRQMASK: 0
>> [58563.146632] GPR00: 0000000000000004 00007fffd3993420 
>> 0000200004557300 0000000000000007
>> [58563.146632] GPR04: 000001000d8a5270 0000000000000006 
>> fffffffffbad2c80 000001000d8a02a0
>> [58563.146632] GPR08: 0000000000000001 0000000000000000 
>> 0000000000000000 0000000000000000
>> [58563.146632] GPR12: 0000000000000000 000020000422bb50 
>> 0000000000000000 0000000000000000
>> [58563.146632] GPR16: 0000000000000000 0000000000000000 
>> 0000000000000000 0000000000000000
>> [58563.146632] GPR20: 0000000000000000 0000000000000000 
>> 0000000000000000 0000000000000000
>> [58563.146632] GPR24: 0000000106b41668 0000000000000000 
>> 0000000000000006 000001000d8a5270
>> [58563.146632] GPR28: 0000000000000006 000001000d8a02a0 
>> 000001000d8a5270 0000000000000006
>> [58563.146690] NIP [0000200004470cb4] 0x200004470cb4
>> [58563.146694] LR [00002000043e7d04] 0x2000043e7d04
>> [58563.146698] --- interrupt: c00
>> [58563.146701] Code: e9299a20 3d020173 39089a20 7fa94000 419e0038 
>> e9490018 7fbf5000 409e0020 48000070 60000000 60000000 60000000 
>> <e9490018> 7faaf840 419e0058 e9290000
>> [58563.146722] ---[ end trace 0000000000000000 ]---
>>
>
-- 
Regards,
Tasmiya Nalatwad
IBM Linux Technology Center