Описание
In the Linux kernel, the following vulnerability has been resolved:
drm/xe/vm: nuke PTs only after unlinking contested VMAs
In xe_vm_close_and_put(), external-BO VMAs are queued on the contested
list for deferred destruction via xe_vma_destroy_unlocked(). However,
xe_vm_pt_destroy() was previously invoked before processing contested
VMAs, destroying vm->pt_root while those VMAs were still linked to their
respective buffer objects (vm_bo->list.gpuva).
If a concurrent thread evicts one of those shared buffer objects,
xe_bo_trigger_rebind() holding only bo->resv walks the BO's VMAs and, in
fault mode, calls xe_vm_invalidate_vma() -> xe_pt_zap_ptes(). Because
vm->pt_root[tile->id] is already NULL, dereferencing pt->level causes a
NULL ptr deref.
Fix this by deferring xe_vm_free_scratch() and xe_vm_pt_destroy() until
after all contested VMAs have been unlinked and destroyed.
User is reporting hitting a NULL ptr deref in xe_pt_zap_ptes(), which
could be explained by this race.
(cherry picked from commit c2863648959489767f08892fd6e90577d2ea0b6a)
A flaw was found in the Linux kernel's Intel Xe graphics driver. When closing a GPU virtual memory space, page tables were destroyed before contested virtual memory areas were properly unlinked from shared buffer objects. A concurrent thread evicting a shared buffer object can attempt to access the already-freed page tables, triggering a NULL pointer dereference. A local user can exploit this race condition to crash the operating system, resulting in a Denial of Service (DoS).
Отчет
This vulnerability is evaluated as a Moderate severity flaw for Red Hat environments because exploitation requires an authenticated local user with access to Intel Xe graphics devices and only leads to a denial of service without compromising confidentiality or integrity. Affected hosts must be running systems equipped with compatible Intel Xe hardware and an active driver instance. Furthermore, triggering the timing condition during GPU virtual memory cleanup leads to a kernel crash rather than arbitrary privilege escalation.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Not affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Not affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Fix deferred |
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Дополнительная информация
Статус:
EPSS
4.7 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: drm/xe/vm: nuke PTs only after unlinking contested VMAs In xe_vm_close_and_put(), external-BO VMAs are queued on the contested list for deferred destruction via xe_vma_destroy_unlocked(). However, xe_vm_pt_destroy() was previously invoked before processing contested VMAs, destroying vm->pt_root while those VMAs were still linked to their respective buffer objects (vm_bo->list.gpuva). If a concurrent thread evicts one of those shared buffer objects, xe_bo_trigger_rebind() holding only bo->resv walks the BO's VMAs and, in fault mode, calls xe_vm_invalidate_vma() -> xe_pt_zap_ptes(). Because vm->pt_root[tile->id] is already NULL, dereferencing pt->level causes a NULL ptr deref. Fix this by deferring xe_vm_free_scratch() and xe_vm_pt_destroy() until after all contested VMAs have been unlinked and destroyed. User is reporting hitting a NULL ptr deref in xe_pt_zap_ptes(), which could be explained by this race. (cherry pic...
In the Linux kernel, the following vulnerability has been resolved: drm/xe/vm: nuke PTs only after unlinking contested VMAs In xe_vm_close_and_put(), external-BO VMAs are queued on the contested list for deferred destruction via xe_vma_destroy_unlocked(). However, xe_vm_pt_destroy() was previously invoked before processing contested VMAs, destroying vm->pt_root while those VMAs were still linked to their respective buffer objects (vm_bo->list.gpuva). If a concurrent thread evicts one of those shared buffer objects, xe_bo_trigger_rebind() holding only bo->resv walks the BO's VMAs and, in fault mode, calls xe_vm_invalidate_vma() -> xe_pt_zap_ptes(). Because vm->pt_root[tile->id] is already NULL, dereferencing pt->level causes a NULL ptr deref. Fix this by deferring xe_vm_free_scratch() and xe_vm_pt_destroy() until after all contested VMAs have been unlinked and destroyed. User is reporting hitting a NULL ptr deref in xe_pt_zap_ptes(), which could be explained by this race. (cherry
In the Linux kernel, the following vulnerability has been resolved: d ...
In the Linux kernel, the following vulnerability has been resolved: drm/xe/vm: nuke PTs only after unlinking contested VMAs In xe_vm_close_and_put(), external-BO VMAs are queued on the contested list for deferred destruction via xe_vma_destroy_unlocked(). However, xe_vm_pt_destroy() was previously invoked before processing contested VMAs, destroying vm->pt_root while those VMAs were still linked to their respective buffer objects (vm_bo->list.gpuva). If a concurrent thread evicts one of those shared buffer objects, xe_bo_trigger_rebind() holding only bo->resv walks the BO's VMAs and, in fault mode, calls xe_vm_invalidate_vma() -> xe_pt_zap_ptes(). Because vm->pt_root[tile->id] is already NULL, dereferencing pt->level causes a NULL ptr deref. Fix this by deferring xe_vm_free_scratch() and xe_vm_pt_destroy() until after all contested VMAs have been unlinked and destroyed. User is reporting hitting a NULL ptr deref in xe_pt_zap_ptes(), which could be explained by this race. (cher...
EPSS
4.7 Medium
CVSS3