Hi Eric, On 2022/3/4 18:34, Eric Auger wrote:
I hit a WARN_ON() when unbinding an e1000e driver just after boot: sudo modprobe -v vfio-pci echo vfio-pci | sudo tee -a /sys/bus/pci/devices/0004:01:00.0/driver_override vfio-pci echo 0004:01:00.0 | sudo tee -a /sys/bus/pci/drivers/e1000e/unbind [ 390.042811] ------------[ cut here ]------------ [ 390.046468] WARNING: CPU: 42 PID: 5589 at drivers/iommu/iommu.c:3123 iommu_device_unuse_default_domain+0x68/0x100 [ 390.056710] Modules linked in: vfio_pci vfio_pci_core vfio_virqfd vfio_iommu_type1 vfio xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 nft_compat nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables nfnetlink bridge stp llc rfkill sunrpc vfat fat mlx5_ib ib_uverbs ib_core acpi_ipmi ipmi_ssif ipmi_devintf ipmi_msghandler cppc_cpufreq drm xfs libcrc32c mlx5_core sg mlxfw crct10dif_ce tls ghash_ce sha2_ce sha256_arm64 sha1_ce sbsa_gwdt e1000e psample sdhci_acpi ahci_platform sdhci libahci_platform qcom_emac mmc_core hdma hdma_mgmt dm_mirror dm_region_hash dm_log dm_mod fuse [ 390.110618] CPU: 42 PID: 5589 Comm: tee Kdump: loaded Not tainted 5.17.0-rc4-lu-v7-official+ #24 [ 390.119384] Hardware name: WIWYNN QDF2400 Reference Evaluation Platform CV90-LA115-P120/QDF2400 Customer Reference Board, BIOS 0ACJA570 11/05/2018 [ 390.132492] pstate: a0400005 (NzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 390.139436] pc : iommu_device_unuse_default_domain+0x68/0x100 [ 390.145165] lr : iommu_device_unuse_default_domain+0x38/0x100 [ 390.150894] sp : ffff80000fbb3bc0 [ 390.154193] x29: ffff80000fbb3bc0 x28: ffff03c0cf6b2400 x27: 0000000000000000 [ 390.161311] x26: 0000000000000000 x25: 0000000000000000 x24: ffff03c0c7cc5720 [ 390.168429] x23: ffff03c0c2b9d150 x22: ffffb4e61df223f8 x21: ffffb4e61df223f8 [ 390.175547] x20: ffff03c7c03c3758 x19: ffff03c7c03c3700 x18: 0000000000000000 [ 390.182665] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 [ 390.189783] x14: 0000000000000000 x13: 0000000000000030 x12: ffff03c0d519cd80 [ 390.196901] x11: 7f7f7f7f7f7f7f7f x10: 0000000000000dc0 x9 : ffffb4e620b54f8c [ 390.204019] x8 : ffff03c0cf6b3220 x7 : ffff4ef132bba000 x6 : 00000000000000ff [ 390.211137] x5 : ffff03c0c2b9f108 x4 : ffff03c0d51f6438 x3 : 0000000000000000 [ 390.218255] x2 : ffff03c0cf6b2400 x1 : 0000000000000000 x0 : 0000000000000000 [ 390.225374] Call trace: [ 390.227804] iommu_device_unuse_default_domain+0x68/0x100 [ 390.233187] pci_dma_cleanup+0x38/0x44 [ 390.236919] __device_release_driver+0x1a8/0x260 [ 390.241519] device_driver_detach+0x50/0xd0 [ 390.245686] unbind_store+0xf8/0x120 [ 390.249245] drv_attr_store+0x30/0x44 [ 390.252891] sysfs_kf_write+0x50/0x60 [ 390.256537] kernfs_fop_write_iter+0x134/0x1cc [ 390.260964] new_sync_write+0xf0/0x18c [ 390.264696] vfs_write+0x230/0x2d0 [ 390.268082] ksys_write+0x74/0x100 [ 390.271467] __arm64_sys_write+0x28/0x3c [ 390.275373] invoke_syscall.constprop.0+0x58/0xf0 [ 390.280061] el0_svc_common.constprop.0+0x160/0x164 [ 390.284922] do_el0_svc+0x34/0xcc [ 390.288221] el0_svc+0x30/0x140 [ 390.291346] el0t_64_sync_handler+0xa4/0x130 [ 390.295599] el0t_64_sync+0x1a0/0x1a4 [ 390.299245] ---[ end trace 0000000000000000 ]--- I put some traces in the code and I can see that iommu_device_use_default_domain() effectively is called on 0004:01:00.0 e1000e device on pci_dma_configure() but at that time the iommu group is NULL: [ 10.569427] e1000e 0004:01:00.0: ------ ENTRY pci_dma_configure driver_managed_area=0 [ 10.569431] e1000e 0004:01:00.0: **** iommu_device_use_default_domain ENTRY [ 10.569433] e1000e 0004:01:00.0: **** iommu_device_use_default_domain no group [ 10.569435] e1000e 0004:01:00.0: pci_dma_configure iommu_device_use_default_domain returned 0 [ 10.569492] e1000e 0004:01:00.0: Adding to iommu group 3 ^^^the group is added after the iommu_device_use_default_domain() call So the group->owner_cnt is not incremented as expected.
Thank you for reporting this. Do you have any idea why the driver is loaded before iommu_probe_device()? Best regards, baolu
