Re: [PATCH] iommu/vt-d: Fix list_add double add when enabling VMD and scalable mode

[Lu Baolu <baolu.lu@linux.intel.com>]

Hi Adrian,

On 2/11/22 10:45 AM, Adrian Huang wrote:
> From: Adrian Huang<ahuang12@lenovo.com>
> 
> When enabling VMD and IOMMU scalable mode, the following kernel panic
> call trace/kernel log is shown in Eagle Stream platform (Sapphire Rapids
> CPU) during booting:
> 
> pci 0000:59:00.5: Adding to iommu group 42
> ...
> vmd 0000:59:00.5: PCI host bridge to bus 10000:80
> pci 10000:80:01.0: [8086:352a] type 01 class 0x060400
> pci 10000:80:01.0: reg 0x10: [mem 0x00000000-0x0001ffff 64bit]
> pci 10000:80:01.0: enabling Extended Tags
> pci 10000:80:01.0: PME# supported from D0 D3hot D3cold
> pci 10000:80:01.0: DMAR: Setup RID2PASID failed
> pci 10000:80:01.0: Failed to add to iommu group 42: -16
> pci 10000:80:03.0: [8086:352b] type 01 class 0x060400
> pci 10000:80:03.0: reg 0x10: [mem 0x00000000-0x0001ffff 64bit]
> pci 10000:80:03.0: enabling Extended Tags
> pci 10000:80:03.0: PME# supported from D0 D3hot D3cold
> list_add double add: new=ff4d61160b74b8a0, prev=ff4d611d8e245c10, next=ff4d61160b74b8a0.
> ------------[ cut here ]------------
> kernel BUG at lib/list_debug.c:29!
> invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
> CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.17.0-rc3+ #7
> Hardware name: Lenovo ThinkSystem SR650V3/SB27A86647, BIOS ESE101Y-1.00 01/13/2022
> Workqueue: events work_for_cpu_fn
> RIP: 0010:__list_add_valid.cold+0x26/0x3f
> Code: 9a 4a ab ff 4c 89 c1 48 c7 c7 40 0c d9 9e e8 b9 b1 fe ff 0f 0b 48 89 f2 4c 89 c1 48 89 fe 48 c7 c7 f0 0c d9 9e e8 a2 b1 fe ff <0f> 0b 48 89 d1 4c 89 c6 4c 89 ca 48 c7 c7 98 0c d9 9e e8 8b b1 fe
> RSP: 0000:ff5ad434865b3a40 EFLAGS: 00010246
> RAX: 0000000000000058 RBX: ff4d61160b74b880 RCX: ff4d61255e1fffa8
> RDX: 0000000000000000 RSI: 00000000fffeffff RDI: ffffffff9fd34f20
> RBP: ff4d611d8e245c00 R08: 0000000000000000 R09: ff5ad434865b3888
> R10: ff5ad434865b3880 R11: ff4d61257fdc6fe8 R12: ff4d61160b74b8a0
> R13: ff4d61160b74b8a0 R14: ff4d611d8e245c10 R15: ff4d611d8001ba70
> FS:  0000000000000000(0000) GS:ff4d611d5ea00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ff4d611fa1401000 CR3: 0000000aa0210001 CR4: 0000000000771ef0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400
> PKRU: 55555554
> Call Trace:
>   <TASK>
>   intel_pasid_alloc_table+0x9c/0x1d0
>   dmar_insert_one_dev_info+0x423/0x540
>   ? device_to_iommu+0x12d/0x2f0
>   intel_iommu_attach_device+0x116/0x290
>   __iommu_attach_device+0x1a/0x90
>   iommu_group_add_device+0x190/0x2c0
>   __iommu_probe_device+0x13e/0x250
>   iommu_probe_device+0x24/0x150
>   iommu_bus_notifier+0x69/0x90
>   blocking_notifier_call_chain+0x5a/0x80
>   device_add+0x3db/0x7b0
>   ? arch_memremap_can_ram_remap+0x19/0x50
>   ? memremap+0x75/0x140
>   pci_device_add+0x193/0x1d0
>   pci_scan_single_device+0xb9/0xf0
>   pci_scan_slot+0x4c/0x110
>   pci_scan_child_bus_extend+0x3a/0x290
>   vmd_enable_domain.constprop.0+0x63e/0x820
>   vmd_probe+0x163/0x190
>   local_pci_probe+0x42/0x80
>   work_for_cpu_fn+0x13/0x20
>   process_one_work+0x1e2/0x3b0
>   worker_thread+0x1c4/0x3a0
>   ? rescuer_thread+0x370/0x370
>   kthread+0xc7/0xf0
>   ? kthread_complete_and_exit+0x20/0x20
>   ret_from_fork+0x1f/0x30
>   </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> ...
> Kernel panic - not syncing: Fatal exception
> Kernel Offset: 0x1ca00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
> ---[ end Kernel panic - not syncing: Fatal exception ]---
> 
> The following 'lspci' output shows devices '10000:80:*' are subdevices of
> the VMD device 0000:59:00.5:
> 
>    $ lspci
>    ...
>    0000:59:00.5 RAID bus controller: Intel Corporation Volume Management Device NVMe RAID Controller (rev 20)
>    ...
>    10000:80:01.0 PCI bridge: Intel Corporation Device 352a (rev 03)
>    10000:80:03.0 PCI bridge: Intel Corporation Device 352b (rev 03)
>    10000:80:05.0 PCI bridge: Intel Corporation Device 352c (rev 03)
>    10000:80:07.0 PCI bridge: Intel Corporation Device 352d (rev 03)
>    10000:81:00.0 Non-Volatile memory controller: Intel Corporation NVMe Datacenter SSD [3DNAND, Beta Rock Controller]
>    10000:82:00.0 Non-Volatile memory controller: Intel Corporation NVMe Datacenter SSD [3DNAND, Beta Rock Controller]
> 
> The symptom 'list_add double add' is caused by the following failure
> message:
> 
>    pci 10000:80:01.0: DMAR: Setup RID2PASID failed
>    pci 10000:80:01.0: Failed to add to iommu group 42: -16
>    pci 10000:80:03.0: [8086:352b] type 01 class 0x060400
> 
> Device 10000:80:01.0 is the subdevice of the VMD device 0000:59:00.5,
> so invoking intel_pasid_alloc_table() gets the pasid_table of the VMD
> device 0000:59:00.5. Here is call path:
> 
>    intel_pasid_alloc_table
>      pci_for_each_dma_alias
>       get_alias_pasid_table
>         search_pasid_table
> 
> pci_real_dma_dev() in pci_for_each_dma_alias() gets the real dma device
> which is the VMD device 0000:59:00.5. However, pte of the VMD device
> 0000:59:00.5 has been configured during this message "pci 0000:59:00.5:
> Adding to iommu group 42". So, the status -EBUSY is returned when
> configuring pasid entry for device 10000:80:01.0.
> 
> It then invokes dmar_remove_one_dev_info() to release
> 'struct device_domain_info *' from iommu_devinfo_cache. But, the pasid
> table is not released because of the following statement in
> __dmar_remove_one_dev_info():
> 
> 	if (info->dev && !dev_is_real_dma_subdevice(info->dev)) {
> 		...
> 		intel_pasid_free_table(info->dev);
>          }
> 
> The subsequent dmar_insert_one_dev_info() operation of device
> 10000:80:03.0 allocates 'struct device_domain_info *' from
> iommu_devinfo_cache. The allocated address is the same address that
> is released previously for device 10000:80:01.0. Finally, invoking
> device_attach_pasid_table() causes the issue.
> 
> The solution is to prevent from allocating pasid table if those
> devices are subdevices of the VMD device.

Thanks for your patch!

Is this the only patch that is needed to make VMD devices work in VT-d
scalable mode?

Best regards,
baolu
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