(release/25.1) composite: Fix PanoramiX overlay window release

[metux]

PanoramiX overlay resources contain physical window IDs for each
screen. Look them up as regular window resources when releasing the
client's overlay reference.

Signed-off-by: Xinhao Liu liuxinhao@kylinsec.com.cn
Part-of: https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2259

[metux]

🤖 Automated review — generated by Starfleet ship Voyager on behalf of @metux. Not a human review.

Correct fix. Inside the XINERAMA_FOR_EACH_SCREEN_BACKWARD loop, win->info[walkScreenIdx].id is a physical per-screen window ID, not a PanoramiX root drawable. Looking it up as XRT_WINDOW was wrong — it should be X11_RESTYPE_WINDOW. The access level DixUnknownAccess (full access) is also unnecessarily broad for a lookup that only reads the window to find overlay clients; DixGetAttrAccess is the minimal correct level.

Note the first lookup (line 770) correctly stays as XRT_WINDOW — stuff->window IS a PanoramiX composite overlay resource.

ABI: ProcCompositeReleaseOverlayWindow is a static function, not exported. Not referenced by any NVIDIA blob. ABI-safe.

Backport candidate (crash/corruption on Xinerama + composite overlay release): likely applies to release/25.0 as well. The bug exists on all Xinerama-enabled builds.