18abda7a2d
The aux-domain attach/detach are not tracked, some data structures might
be used after free. This causes general protection faults when multiple
subdevices are created and assigned to a same guest machine:
| general protection fault, probably for non-canonical address 0xdead000000000100: 0000 [#1] SMP NOPTI
| RIP: 0010:intel_iommu_aux_detach_device+0x12a/0x1f0
| [...]
| Call Trace:
| iommu_aux_detach_device+0x24/0x70
| vfio_mdev_detach_domain+0x3b/0x60
| ? vfio_mdev_set_domain+0x50/0x50
| iommu_group_for_each_dev+0x4f/0x80
| vfio_iommu_detach_group.isra.0+0x22/0x30
| vfio_iommu_type1_detach_group.cold+0x71/0x211
| ? find_exported_symbol_in_section+0x4a/0xd0
| ? each_symbol_section+0x28/0x50
| __vfio_group_unset_container+0x4d/0x150
| vfio_group_try_dissolve_container+0x25/0x30
| vfio_group_put_external_user+0x13/0x20
| kvm_vfio_group_put_external_user+0x27/0x40 [kvm]
| kvm_vfio_destroy+0x45/0xb0 [kvm]
| kvm_put_kvm+0x1bb/0x2e0 [kvm]
| kvm_vm_release+0x22/0x30 [kvm]
| __fput+0xcc/0x260
| ____fput+0xe/0x10
| task_work_run+0x8f/0xb0
| do_exit+0x358/0xaf0
| ? wake_up_state+0x10/0x20
| ? signal_wake_up_state+0x1a/0x30
| do_group_exit+0x47/0xb0
| __x64_sys_exit_group+0x18/0x20
| do_syscall_64+0x57/0x1d0
| entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fix the crash by tracking the subdevices when attaching and detaching
aux-domains.
Fixes: 67b8e02b5e ("iommu/vt-d: Aux-domain specific domain attach/detach")
Co-developed-by: Xin Zeng <xin.zeng@intel.com>
Signed-off-by: Xin Zeng <xin.zeng@intel.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/1609949037-25291-3-git-send-email-yi.l.liu@intel.com
Signed-off-by: Will Deacon <will@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.