High [CVE-2026-53201] Revert "drm/xe: Skip exec queue schedule toggle if queue is idle during suspend"

In the Linux kernel, the following vulnerability has been resolved: Revert "drm/xe: Skip exec queue schedule toggle if queue is idle during suspend" This reverts commit 8533051ce92015e9cc6f75e0d52119b9d91610b6. The idle-skip optimization bypasses GuC suspend, so the GPU may not perform the context switch that flushes TLB entries for invalidated userptr VMAs.

In LR/preempt-fence VM mode, this can lead to missed TLB invalidation and page faults during userptr invalidation tests. Restore unconditional schedule toggling on suspend so the context-switch TLB flush is always performed.

This optimization will be reintroduced with a fix that does not skip suspend in LR/preempt-fence VM mode. (cherry picked from commit 6a1e7934d9a6cf46aecae00a99c2603d1295e170) A flaw was found in the Linux kernel's `drm/xe` graphics driver.

An optimization intended to skip execution queue schedule toggling during GPU suspend could bypass a critical GuC suspend operation. This bypass prevents the GPU from properly flushing Translation Lookaside Buffer (TLB) entries for invalidated user memory areas, particularly in specific virtual memory modes.

A local attacker could exploit this to cause missed TLB invalidations and page faults, potentially leading to information disclosure or a denial of service. Red Hat severity: Important — CVSS 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).