linux-cve-announce - CVE-2025-68286: drm/amd/display: Check NULL before accessing

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Message-ID: <2025121638-CVE-2025-68286-cda3@gregkh>
Date: Tue, 16 Dec 2025 16:06:40 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-68286: drm/amd/display: Check NULL before accessing

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

drm/amd/display: Check NULL before accessing

[WHAT]
IGT kms_cursor_legacy's long-nonblocking-modeset-vs-cursor-atomic
fails with NULL pointer dereference. This can be reproduced with
both an eDP panel and a DP monitors connected.

 BUG: kernel NULL pointer dereference, address: 0000000000000000
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: Oops: 0000 [#1] SMP NOPTI
 CPU: 13 UID: 0 PID: 2960 Comm: kms_cursor_lega Not tainted
6.16.0-99-custom #8 PREEMPT(voluntary)
 Hardware name: AMD ........
 RIP: 0010:dc_stream_get_scanoutpos+0x34/0x130 [amdgpu]
 Code: 57 4d 89 c7 41 56 49 89 ce 41 55 49 89 d5 41 54 49
 89 fc 53 48 83 ec 18 48 8b 87 a0 64 00 00 48 89 75 d0 48 c7 c6 e0 41 30
 c2 <48> 8b 38 48 8b 9f 68 06 00 00 e8 8d d7 fd ff 31 c0 48 81 c3 e0 02
 RSP: 0018:ffffd0f3c2bd7608 EFLAGS: 00010292
 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffd0f3c2bd7668
 RDX: ffffd0f3c2bd7664 RSI: ffffffffc23041e0 RDI: ffff8b32494b8000
 RBP: ffffd0f3c2bd7648 R08: ffffd0f3c2bd766c R09: ffffd0f3c2bd7760
 R10: ffffd0f3c2bd7820 R11: 0000000000000000 R12: ffff8b32494b8000
 R13: ffffd0f3c2bd7664 R14: ffffd0f3c2bd7668 R15: ffffd0f3c2bd766c
 FS:  000071f631b68700(0000) GS:ffff8b399f114000(0000)
knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000000 CR3: 00000001b8105000 CR4: 0000000000f50ef0
 PKRU: 55555554
 Call Trace:
 <TASK>
 dm_crtc_get_scanoutpos+0xd7/0x180 [amdgpu]
 amdgpu_display_get_crtc_scanoutpos+0x86/0x1c0 [amdgpu]
 ? __pfx_amdgpu_crtc_get_scanout_position+0x10/0x10[amdgpu]
 amdgpu_crtc_get_scanout_position+0x27/0x50 [amdgpu]
 drm_crtc_vblank_helper_get_vblank_timestamp_internal+0xf7/0x400
 drm_crtc_vblank_helper_get_vblank_timestamp+0x1c/0x30
 drm_crtc_get_last_vbltimestamp+0x55/0x90
 drm_crtc_next_vblank_start+0x45/0xa0
 drm_atomic_helper_wait_for_fences+0x81/0x1f0
 ...

(cherry picked from commit 621e55f1919640acab25383362b96e65f2baea3c)

The Linux kernel CVE team has assigned CVE-2025-68286 to this issue.


Affected and fixed versions
===========================

	Fixed in 5.10.247 with commit 781f2f32e9c19eb791b52af283c96f9a9677a7f2
	Fixed in 5.15.197 with commit 09092269cb762378ca8b56024746b1a136761e0d
	Fixed in 6.1.159 with commit 109e9c92543f3105e8e1efd2c5e6b92ef55d5743
	Fixed in 6.6.119 with commit 9d1a65cbe3ec5da3003c8434ac7a38dcdc958fd9
	Fixed in 6.12.61 with commit f7cf491cd5b54b5a093bd3fdf76fa2860a7522bf
	Fixed in 6.17.11 with commit 62150f1e7ec707da76ff353fb7db51fef9cd6557
	Fixed in 6.18 with commit 3ce62c189693e8ed7b3abe551802bbc67f3ace54

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-68286
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/gpu/drm/amd/display/dc/core/dc_stream.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/781f2f32e9c19eb791b52af283c96f9a9677a7f2
	https://git.kernel.org/stable/c/09092269cb762378ca8b56024746b1a136761e0d
	https://git.kernel.org/stable/c/109e9c92543f3105e8e1efd2c5e6b92ef55d5743
	https://git.kernel.org/stable/c/9d1a65cbe3ec5da3003c8434ac7a38dcdc958fd9
	https://git.kernel.org/stable/c/f7cf491cd5b54b5a093bd3fdf76fa2860a7522bf
	https://git.kernel.org/stable/c/62150f1e7ec707da76ff353fb7db51fef9cd6557
	https://git.kernel.org/stable/c/3ce62c189693e8ed7b3abe551802bbc67f3ace54