drm/amd/display: dce100: skip non-DP stream encoders for DP MST
Summary
| CVE | CVE-2026-68235 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-08-10 13:20:11 UTC |
| Updated | 2026-08-18 07:16:50 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: dce100: skip non-DP stream encoders for DP MST On DCE8-class ASICs (e.g. Bonaire), the resource pool contains digital DIG stream encoders plus one analog DAC encoder. When assigning a stream encoder for a second DisplayPort MST stream, if the preferred digital encoder is already acquired, dce100_find_first_free_match_stream_enc_for_link() falls back to the first free pool entry. That entry may be the analog encoder, whose funcs table lacks DP hooks such as dp_set_stream_attribute. The subsequent atomic commit then dereferences NULL function pointers in link_set_dpms_on() and crashes. Skip encoders without dp_set_stream_attribute when the stream uses a DP signal (including MST). Use dc_is_dp_signal(stream->signal) for the MST fallback path instead of checking only the link connector signal. Tested on: - GPU: AMD Radeon R7 260X (Bonaire / DCE8) - Board: Supermicro C9X299-PG300 - Setup: DP MST daisy chain, hotplug second monitor or have it connected on boot - Kernel: 7.1.3 (issue observed since 6.19) - Result: kernel oops without patch; dual monitors stable with patch (cherry picked from commit 28ec64943e3ee4d9b8d30cea61e380f1429953a8) |
Risk And Classification
EPSS: 0.001980000 probability, percentile 0.098880000 (date 2026-08-18)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 5834c33fd3f6f2a26dd4d6d4bbc7b8ed1c2ac4aa ed2d86aef9fa4c43f82da0fca91a60f7326d7d03 git | Not specified |
| CNA | Linux | Linux | affected 5834c33fd3f6f2a26dd4d6d4bbc7b8ed1c2ac4aa d340cba0df4cf327c7e89c7c1a4e79d4771d7dd5 git | Not specified |
| CNA | Linux | Linux | affected 6.19 | Not specified |
| CNA | Linux | Linux | unaffected 6.19 semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1.6 7.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/d340cba0df4cf327c7e89c7c1a4e79d4771d7dd5 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/ed2d86aef9fa4c43f82da0fca91a60f7326d7d03 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/51ea665c30c424c98959101f3bf6f48ab42949c8 | MITRE | git.kernel.org | |
| git.kernel.org/stable/c/bfe28ce019c2d667d98071262da33d8bba122919 | MITRE | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.