Re: [BUG REPORT]net: page_pool: kernel crash at iommu_get_dma_domain+0xc/0x20

[Yonglong Liu <liuyonglong@huawei.com>]

On 2024/7/31 16:42, Somnath Kotur wrote:
> On Tue, Jul 30, 2024 at 10:51 PM Jesper Dangaard Brouer <hawk@kernel.org> wrote:
>>
>>
>> On 30/07/2024 15.08, Yonglong Liu wrote:
>>> I found a bug when running hns3 driver with page pool enabled, the log
>>> as below:
>>>
>>> [ 4406.956606] Unable to handle kernel NULL pointer dereference at
>>> virtual address 00000000000000a8
>> struct iommu_domain *iommu_get_dma_domain(struct device *dev)
>> {
>>          return dev->iommu_group->default_domain;
>> }
>>
>> $ pahole -C iommu_group --hex | grep default_domain
>>          struct iommu_domain *      default_domain;   /*  0xa8   0x8 */
>>
>> Looks like iommu_group is a NULL pointer (that when deref member
>> 'default_domain' cause this fault).
>>
>>
>>> [ 4406.965379] Mem abort info:
>>> [ 4406.968160]   ESR = 0x0000000096000004
>>> [ 4406.971906]   EC = 0x25: DABT (current EL), IL = 32 bits
>>> [ 4406.977218]   SET = 0, FnV = 0
>>> [ 4406.980258]   EA = 0, S1PTW = 0
>>> [ 4406.983404]   FSC = 0x04: level 0 translation fault
>>> [ 4406.988273] Data abort info:
>>> [ 4406.991154]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
>>> [ 4406.996632]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
>>> [ 4407.001681]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
>>> [ 4407.006985] user pgtable: 4k pages, 48-bit VAs, pgdp=0000202828326000
>>> [ 4407.013430] [00000000000000a8] pgd=0000000000000000,
>>> p4d=0000000000000000
>>> [ 4407.020212] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
>>> [ 4407.026454] Modules linked in: hclgevf xt_CHECKSUM ipt_REJECT
>>> nf_reject_ipv4 ip6table_mangle ip6table_nat iptable_mangle
>>> ip6table_filter ip6_tables hns_roce_hw_v2 hns3 hclge hnae3 xt_addrtype
>>> iptable_filter xt_conntrack overlay arm_spe_pmu arm_smmuv3_pmu
>>> hisi_uncore_hha_pmu hisi_uncore_ddrc_pmu hisi_uncore_l3c_pmu
>>> hisi_uncore_pmu fuse rpcrdma ib_isert iscsi_target_mod ib_iser libiscsi
>>> scsi_transport_iscsi crct10dif_ce hisi_sec2 hisi_hpre hisi_zip
>>> hisi_sas_v3_hw xhci_pci sbsa_gwdt hisi_qm hisi_sas_main hisi_dma
>>> xhci_pci_renesas uacce libsas [last unloaded: hnae3]
>>> [ 4407.076027] CPU: 48 PID: 610 Comm: kworker/48:1
>>> [ 4407.093343] Workqueue: events page_pool_release_retry
>>> [ 4407.098384] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS
>>> BTYPE=--)
>>> [ 4407.105316] pc : iommu_get_dma_domain+0xc/0x20
>>> [ 4407.109744] lr : iommu_dma_unmap_page+0x38/0xe8
>>> [ 4407.114255] sp : ffff80008bacbc80
>>> [ 4407.117554] x29: ffff80008bacbc80 x28: 0000000000000000 x27:
>>> ffffc31806be7000
>>> [ 4407.124659] x26: ffff2020002b6ac0 x25: 0000000000000000 x24:
>>> 0000000000000002
>>> [ 4407.131762] x23: 0000000000000022 x22: 0000000000001000 x21:
>>> 00000000fcd7c000
>>> [ 4407.138865] x20: ffff0020c9882800 x19: ffff0020856f60c8 x18:
>>> ffff8000d3503c58
>>> [ 4407.145968] x17: 0000000000000000 x16: 1fffe00419521061 x15:
>>> 0000000000000001
>>> [ 4407.153073] x14: 0000000000000003 x13: 00000401850ae012 x12:
>>> 000006b10004e7fb
>>> [ 4407.160177] x11: 0000000000000067 x10: 0000000000000c70 x9 :
>>> ffffc3180405cd20
>>> [ 4407.167280] x8 : fefefefefefefeff x7 : 0000000000000001 x6 :
>>> 0000000000000010
>>> [ 4407.174382] x5 : ffffc3180405cce8 x4 : 0000000000000022 x3 :
>>> 0000000000000002
>>> [ 4407.181485] x2 : 0000000000001000 x1 : 00000000fcd7c000 x0 :
>>> 0000000000000000
>>> [ 4407.188589] Call trace:
>>> [ 4407.191027]  iommu_get_dma_domain+0xc/0x20
>>> [ 4407.195105]  dma_unmap_page_attrs+0x38/0x1d0
>>> [ 4407.199361]  page_pool_return_page+0x48/0x180
>>> [ 4407.203699]  page_pool_release+0xd4/0x1f0
>>> [ 4407.207692]  page_pool_release_retry+0x28/0xe8
>> I suspect that the DMA IOMMU part was deallocated and freed by the
>> driver even-though page_pool still have inflight packets.
> When you say driver, which 'driver' do you mean?
> I suspect this could be because of the VF instance going away with
> this cmd - disable the vf: echo 0 >
> /sys/class/net/eno1/device/sriov_numvfs, what do you think?

I found that this happen when the vf enabled and running some packets, 
below is more infomation:


[ 4391.596558] pci 0000:7d:01.0: page_pool_release_retry() stalled pool 
shutdown: id 1145, 33 inflight 906 sec
[ 4397.111484] hns3 0000:bd:00.0: SRIOV setting: 0
[ 4397.118155] hns3 0000:bd:01.0 enp189s0f0v0: link down
[ 4397.416623] hns3 0000:bd:01.0: finished uninitializing hclgevf driver
[ 4397.480572] pci 0000:7d:01.0: page_pool_release_retry() stalled pool 
shutdown: id 1279, 98 inflight 362 sec
[ 4400.948362] hns3 0000:7d:00.0: SRIOV setting: 1
[ 4401.060569] pci 0000:7d:01.0: [19e5:a22f] type 00 class 0x020000 PCIe 
Endpoint
[ 4401.067795] pci 0000:7d:01.0: enabling Extended Tags
[ 4401.073090] hns3 0000:7d:01.0: Adding to iommu group 48
[ 4401.078494] hns3 0000:7d:01.0: enabling device (0000 -> 0002)
[ 4401.084348] hns3 0000:7d:01.0: The firmware version is 1.20.0.17
[ 4401.102911] hns3 0000:7d:01.0: finished initializing hclgevf driver
[ 4401.111212] hns3 0000:7d:01.0: using random MAC address da:**:**:**:a3:47
[ 4401.138375] hns3 0000:7d:01.0 eno1v0: renamed from eth0
[ 4403.939449] hns3 0000:7d:01.0 eno1v0: link up
[ 4403.940237] 8021q: adding VLAN 0 to HW filter on device eno1v0
[ 4406.956606] Unable to handle kernel NULL pointer dereference at 
virtual address 00000000000000a8


another log:

[11550.197002] hns3 0000:bd:01.0 enp189s0f0v0: link up
[11550.197034] hns3 0000:bd:01.0 enp189s0f0v0: net open
[11550.206910] 8021q: adding VLAN 0 to HW filter on device enp189s0f0v0
[11564.872929] page_pool_release_retry() stalled pool shutdown: id 2330, 
99 inflight 60 sec
[11568.353723] hns3 0000:bd:01.0 enp189s0f0v0: net stop
[11568.360723] hns3 0000:bd:01.0 enp189s0f0v0: link down
[11568.519899] hns3 0000:bd:01.0 enp189s0f0v0: link up
[11568.519935] hns3 0000:bd:01.0 enp189s0f0v0: net open
[11568.529840] 8021q: adding VLAN 0 to HW filter on device enp189s0f0v0
[11589.640930] page_pool_release_retry() stalled pool shutdown: id 1996, 
50 inflight 2054 sec
[11592.554875] hns3 0000:bd:01.0 enp189s0f0v0: net stop
[11592.560930] hns3 0000:bd:01.0 enp189s0f0v0: link down
[11596.684935] pci 0000:7d:01.0: [19e5:a22f] type 00 class 0x020000 PCIe 
Endpoint
[11596.692140] pci 0000:7d:01.0: enabling Extended Tags
[11596.697324] hns3 0000:7d:01.0: Adding to iommu group 48
[11596.702988] hns3 0000:7d:01.0: enabling device (0000 -> 0002)
[11596.708808] hns3 0000:7d:01.0: The firmware version is 1.20.0.17
[11596.727263] hns3 0000:7d:01.0: finished initializing hclgevf driver
[11596.735561] hns3 0000:7d:01.0: using random MAC address 72:**:**:**:55:d7
[11596.760621] hns3 0000:7d:01.0 eno1v0: renamed from eth0
[11599.545341] hns3 0000:7d:01.0 eno1v0: link up
[11599.545409] hns3 0000:7d:01.0 eno1v0: net open
[11599.554858] 8021q: adding VLAN 0 to HW filter on device eno1v0
[11608.908922] Unable to handle kernel NULL pointer dereference at 
virtual address 00000000000000a8


>> The page_pool bumps refcnt via get_device() + put_device() on the DMA
>> 'struct device', to avoid it going away, but I guess there is also some
>> IOMMU code that we need to make sure doesn't go away (until all inflight
>> pages are returned) ???
>>
>>
>>> [ 4407.212119]  process_one_work+0x164/0x3e0
>>> [ 4407.216116]  worker_thread+0x310/0x420
>>> [ 4407.219851]  kthread+0x120/0x130
>>> [ 4407.223066]  ret_from_fork+0x10/0x20
>>> [ 4407.226630] Code: ffffc318 aa1e03e9 d503201f f9416c00 (f9405400)
>>> [ 4407.232697] ---[ end trace 0000000000000000 ]---
>>>
>>>
>>> The hns3 driver use page pool like this, just call once when the driver
>>> initialize:
>>>
>>> static void hns3_alloc_page_pool(struct hns3_enet_ring *ring)
>>> {
>>>       struct page_pool_params pp_params = {
>>>           .flags = PP_FLAG_DMA_MAP | PP_FLAG_PAGE_FRAG |
>>>                   PP_FLAG_DMA_SYNC_DEV,
>>>           .order = hns3_page_order(ring),
>>>           .pool_size = ring->desc_num * hns3_buf_size(ring) /
>>>                   (PAGE_SIZE << hns3_page_order(ring)),
>>>           .nid = dev_to_node(ring_to_dev(ring)),
>>>           .dev = ring_to_dev(ring),
>>>           .dma_dir = DMA_FROM_DEVICE,
>>>           .offset = 0,
>>>           .max_len = PAGE_SIZE << hns3_page_order(ring),
>>>       };
>>>
>>>       ring->page_pool = page_pool_create(&pp_params);
>>>       if (IS_ERR(ring->page_pool)) {
>>>           dev_warn(ring_to_dev(ring), "page pool creation failed: %ld\n",
>>>                PTR_ERR(ring->page_pool));
>>>           ring->page_pool = NULL;
>>>       }
>>> }
>>>
>>> And call page_pool_destroy(ring->page_pool)  when the driver uninitialized.
>>>
>>>
>>> We use two devices, the net port connect directory, and the step of the
>>> test case like below:
>>>
>>> 1. enable a vf of '7d:00.0':  echo 1 >
>>> /sys/class/net/eno1/device/sriov_numvfs
>>>
>>> 2. use iperf to produce some flows(the problem happens to the side which
>>> runs 'iperf -s')
>>>
>>> 3. use ifconfig down/up to the vf
>>>
>>> 4. kill iperf
>>>
>>> 5. disable the vf: echo 0 > /sys/class/net/eno1/device/sriov_numvfs
>>>
>>> 6. run 1~5 with another port bd:00.0
>>>
>>> 7. repeat 1~6
>>>
>>>
>>> And when running this test case, we can found another related message (I
>>> replaced pr_warn() to dev_warn()):
>>>
>>> pci 0000:7d:01.0: page_pool_release_retry() stalled pool shutdown: id
>>> 949, 98 inflight 1449 sec
>>>
>>>
>>> Even when stop the traffic, stop the test case, disable the vf, this
>>> message is still being printed.
>>>
>>> We must run the test case for about two hours to reproduce the problem.
>>> Is there some advise to solve or debug the problem?
>>>