Re: [PATCH v5 19/20] vfio: selftests: Verify that opening VFIO device fails during Live Update

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:
- [Medium] Test assertion failure due to IOMMU group already being claimed by preserved cdev
- [Medium] Test assertion failure due to re-binding already bound preserved cdev
- [Low] Abstraction violation using free() instead of vfio_pci_device_free()
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--- Patch [19]: [PATCH v5 19/20] vfio: selftests: Verify that opening VFIO device fails during Live Update ---
Note: Due to recitation restrictions, this report uses a free-form summary
of the findings rather than quoting the original patch diff.

commit b5a56d527567933e2f5fd3077aed99e8404f21c3
Author: David Matlack <dmatlack@google.com>
Subject: vfio: selftests: Verify that opening VFIO device fails during Live Update

This patch verifies that opening a VFIO device through its cdev file and via
VFIO_GROUP_GET_DEVICE_FD both fail with -EBUSY if the device was preserved
across a Live Update.

[Severity: Medium]
In check_open_vfio_device_fails(), the test loops over legacy modes and
calls vfio_pci_group_setup(). Since the device is already opened via cdev
before kexec, the group's cdev_device_open_cnt is greater than zero. 

Does this cause the group open attempt inside vfio_pci_group_setup() to
fail with EBUSY? If so, it looks like this will trigger the VFIO_ASSERT_GE()
assertion on the group_fd, which would abort the test before it can even
reach the VFIO_GROUP_GET_DEVICE_FD ioctl it is intended to verify.

[Severity: Medium]
In after_kexec(), the test retrieves the preserved device_fd and attempts to
initialize it with a newly created iommufd by calling
__vfio_pci_device_init(), which then issues the VFIO_DEVICE_BIND_IOMMUFD
ioctl.

Because the device_fd is preserved across the Live Update, doesn't it still
retain its original binding state and reference to the original iommufd
context? It appears this might cause the bind ioctl to return -EINVAL,
triggering a fatal VFIO_ASSERT_EQ() in vfio_device_bind_iommufd() and
crashing the test.

[Severity: Low]
In check_open_vfio_device_fails(), the code directly calls free(device) on
the pointer returned by vfio_pci_device_alloc().

Would it be better to use vfio_pci_device_free() here instead? Even if it
only wraps free() currently, using the library's abstraction might help
prevent future memory leaks if internal allocations are added later.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260714151505.3466855-1-vipinsh@google.com?part=19