drm/xe: skip eviction of a BO with no resource
Impact
In the Linux kernel, the following vulnerability has been resolved:
Source excerpt · LinuxAffected packages
Affected products
Vendor version evidence. Product records are separate from automatic dependency matching.
Linux · Linux
Other versions: unaffected
| Version / range | Source status |
|---|---|
| dd08ebf6c3525a7ea2186e636df064ea47281987 to before 6046bb9cb2859e3d9bf939e4d6527f3827e1096f | affected |
| dd08ebf6c3525a7ea2186e636df064ea47281987 to before b6499d19ade1f1e4a1e6b739abc8c815297c98b8 | affected |
| dd08ebf6c3525a7ea2186e636df064ea47281987 to before 448e76cbdc6652ccd3ba337b7a6e1f028859f2ed | affected |
Linux · Linux
Other versions: affected
| Version / range | Source status |
|---|---|
| 6.8 | affected |
| 0 to before 6.8 | unaffected |
| 6.18.59 through 6.18.* (inclusive) | unaffected |
| 7.2.13 through 7.2.* (inclusive) | unaffected |
| 7.3 through * (inclusive) | unaffected |
Original source description
In the Linux kernel, the following vulnerability has been resolved:
drm/xe: skip eviction of a BO with no resource
xe_evict_flags() switches on tbo->resource->mem_type to choose an eviction placement. An xe BO can reach eviction with no ttm.resource, e.g. an imported dma-buf BO whose resource was freed during teardown while its attachment is still live: the exporter then invalidates it via xe_dma_buf_move_notify() -> xe_bo_evict(), and the switch dereferences a NULL resource and faults.
A BO with no resource has nothing placed or mapped, so there is nothing to evict. Return an empty placement (num_placement = 0), mirroring the handling already used for non-xe scatter-gather BOs just above; ttm_bo_validate() then takes the pipeline-gutting path and returns 0.
Without the fix the xe_dma_buf@xe_test_dmabuf_move_notify_no_resource dynamic live selftest will fail with below stack.
BUG: kernel NULL pointer dereference, address: 0000000000000010 RIP: 0010:xe_evict_flags+0xf4/0x140 [xe] Call Trace: <TASK> xe_bo_evict+0x40/0xa0 [xe] ? ttm_bo_pipeline_gutting+0x71/0x180 [ttm] xe_test_dmabuf_move_notify_no_resource+0x182/0x440 [xe] xe_dma_buf_kunit+0x387/0x580 [xe]
v2: Add Fixes tag and failure info in commit text (Matt Brost)
(cherry picked from commit dbcfaac6331f1fcb0c2fe3ad3e9adb1e5d43ec0c)