Re: [RESEND PATCH v8 00/11] Fix BUG_ON in vfio_iommu_group_notifier()

[Qian Cai]

On Mon, Apr 18, 2022 at 08:49:49AM +0800, Lu Baolu wrote:
> Hi Joerg,
> 
> This is a resend version of v8 posted here:
> https://lore.kernel.org/linux-iommu/20220308054421.847385-1-baolu.lu@xxxxxxxxxxxxxxx/
> as we discussed in this thread:
> https://lore.kernel.org/linux-iommu/Yk%2Fq1BGN8pC5HVZp@xxxxxxxxxx/
> 
> All patches can be applied perfectly except this one:
>  - [PATCH v8 02/11] driver core: Add dma_cleanup callback in bus_type
> It conflicts with below refactoring commit:
>  - 4b775aaf1ea99 "driver core: Refactor sysfs and drv/bus remove hooks"
> The conflict has been fixed in this post.
> 
> No functional changes in this series. I suppress cc-ing this series to
> all v8 reviewers in order to avoid spam.
> 
> Please consider it for your iommu tree.

Reverting this series fixed an user-after-free while doing SR-IOV.

 BUG: KASAN: use-after-free in __lock_acquire
 Read of size 8 at addr ffff080279825d78 by task qemu-system-aar/22429
 CPU: 24 PID: 22429 Comm: qemu-system-aar Not tainted 5.18.0-rc5-next-20220502 #69
 Call trace:
  dump_backtrace
  show_stack
  dump_stack_lvl
  print_address_description.constprop.0
  print_report
  kasan_report
  __asan_report_load8_noabort
  __lock_acquire
  lock_acquire.part.0
  lock_acquire
  _raw_spin_lock_irqsave
  arm_smmu_detach_dev
  arm_smmu_detach_dev at drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c:2377
  arm_smmu_attach_dev
  __iommu_attach_group
  __iommu_attach_device at drivers/iommu/iommu.c:1942
  (inlined by) iommu_group_do_attach_device at drivers/iommu/iommu.c:2058
  (inlined by) __iommu_group_for_each_dev at drivers/iommu/iommu.c:989
  (inlined by) __iommu_attach_group at drivers/iommu/iommu.c:2069
  iommu_group_release_dma_owner
  __vfio_group_unset_container
  vfio_group_try_dissolve_container
  vfio_group_put_external_user
  kvm_vfio_destroy
  kvm_destroy_vm
  kvm_vm_release
  __fput
  ____fput
  task_work_run
  do_exit
  do_group_exit
  get_signal
  do_signal
  do_notify_resume
  el0_svc
  el0t_64_sync_handler
  el0t_64_sync

 Allocated by task 22427:
  kasan_save_stack
  __kasan_kmalloc
  kmem_cache_alloc_trace
  arm_smmu_domain_alloc
  iommu_domain_alloc
  vfio_iommu_type1_attach_group
  vfio_ioctl_set_iommu
  vfio_fops_unl_ioctl
  __arm64_sys_ioctl
  invoke_syscall
  el0_svc_common.constprop.0
  do_el0_svc
  el0_svc
  el0t_64_sync_handler
  el0t_64_sync

 Freed by task 22429:
  kasan_save_stack
  kasan_set_track
  kasan_set_free_info
  ____kasan_slab_free
  __kasan_slab_free
  slab_free_freelist_hook
  kfree
  arm_smmu_domain_free
  arm_smmu_domain_free at iommu/arm/arm-smmu-v3/arm-smmu-v3.c:2067
  iommu_domain_free
  vfio_iommu_type1_detach_group
  __vfio_group_unset_container
  vfio_group_try_dissolve_container
  vfio_group_put_external_user
  kvm_vfio_destroy
  kvm_destroy_vm
  kvm_vm_release
  __fput
  ____fput
  task_work_run
  do_exit
  do_group_exit
  get_signal
  do_signal
  do_notify_resume
  el0_svc
  el0t_64_sync_handler
  el0t_64_sync