drm/xe: Don't transfer shrinker pages for pinned bos on purgeable state change
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 |
|---|---|
| 536a2ead3a8f2048643da3e8340a4d73fdf71903 to before 135e998dd1e66b8854db7bd356b6563baf8b9d51 | affected |
| 536a2ead3a8f2048643da3e8340a4d73fdf71903 to before ffbfd3f98f4393e91dffce3a46ccb7cf5329cf2f | affected |
Linux · Linux
Other versions: affected
| Version / range | Source status |
|---|---|
| 7.1 | affected |
| 0 to before 7.1 | 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: Don't transfer shrinker pages for pinned bos on purgeable state change
Pinned bos have their pages removed from the shrinker's shrinkable / purgeable counts on pin, and added back on unpin according to the bo's purgeable state at that time.
However, xe_bo_set_purgeable_shrinker() unconditionally transfers pages between the shrinkable and purgeable counts. If the purgeable state of a pinned bo changes, for example by userspace madvising DONTNEED on a VMA of a bo that is also pinned as a scanout buffer, this underflows one count and, after unpin, leaves the other one permanently inflated.
Only update the purgeable flag for pinned bos, and leave the page accounting to unpin.
(cherry picked from commit afe6bc012034123fd838328668e609bf57e46bd3)