Bug 2422684 (CVE-2025-68184)

Summary: CVE-2025-68184 kernel: Linux kernel drm/mediatek: Denial of Service due to broken AFBC support on Mediatek MT8188
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the `drm/mediatek` driver of the Linux kernel. When Arm Frame Buffer Compression (AFBC) support is enabled on Mediatek MT8188 platforms, it can lead to constant vblank timeouts and garbled display rendering. This issue can result in system instability and a denial of service related to the display functionality.
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2025-12-16 14:03:35 UTC
In the Linux kernel, the following vulnerability has been resolved:

drm/mediatek: Disable AFBC support on Mediatek DRM driver

Commit c410fa9b07c3 ("drm/mediatek: Add AFBC support to Mediatek DRM
driver") added AFBC support to Mediatek DRM and enabled the
32x8/split/sparse modifier.

However, this is currently broken on Mediatek MT8188 (Genio 700 EVK
platform); tested using upstream Kernel and Mesa (v25.2.1), AFBC is used by
default since Mesa v25.0.

Kernel trace reports vblank timeouts constantly, and the render is garbled:

```
[CRTC:62:crtc-0] vblank wait timed out
WARNING: CPU: 7 PID: 70 at drivers/gpu/drm/drm_atomic_helper.c:1835 drm_atomic_helper_wait_for_vblanks.part.0+0x24c/0x27c
[...]
Hardware name: MediaTek Genio-700 EVK (DT)
Workqueue: events_unbound commit_work
pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : drm_atomic_helper_wait_for_vblanks.part.0+0x24c/0x27c
lr : drm_atomic_helper_wait_for_vblanks.part.0+0x24c/0x27c
sp : ffff80008337bca0
x29: ffff80008337bcd0 x28: 0000000000000061 x27: 0000000000000000
x26: 0000000000000001 x25: 0000000000000000 x24: ffff0000c9dcc000
x23: 0000000000000001 x22: 0000000000000000 x21: ffff0000c66f2f80
x20: ffff0000c0d7d880 x19: 0000000000000000 x18: 000000000000000a
x17: 000000040044ffff x16: 005000f2b5503510 x15: 0000000000000000
x14: 0000000000000000 x13: 74756f2064656d69 x12: 742074696177206b
x11: 0000000000000058 x10: 0000000000000018 x9 : ffff800082396a70
x8 : 0000000000057fa8 x7 : 0000000000000cce x6 : ffff8000823eea70
x5 : ffff0001fef5f408 x4 : ffff80017ccee000 x3 : ffff0000c12cb480
x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000c12cb480
Call trace:
 drm_atomic_helper_wait_for_vblanks.part.0+0x24c/0x27c (P)
 drm_atomic_helper_commit_tail_rpm+0x64/0x80
 commit_tail+0xa4/0x1a4
 commit_work+0x14/0x20
 process_one_work+0x150/0x290
 worker_thread+0x2d0/0x3ec
 kthread+0x12c/0x210
 ret_from_fork+0x10/0x20
---[ end trace 0000000000000000 ]---
```

Until this gets fixed upstream, disable AFBC support on this platform, as
it's currently broken with upstream Mesa.