DF-4861

aux_engine_funcs.configure left NULL in the dce110 (and all i2caux) AUX engine func tables while dal_i2caux_configure_aux() invokes it unconditionally — latent NULL function-pointer call/panic on any future caller

Summary

Designated-initializer semantics leave .configure NULL in every i2caux engine table while the exported configure API calls it unguarded - a guaranteed NULL fn-ptr panic the moment any future display-reconfig path uses the API (DCE 8.x-11.2). Zero callers today (latent dead-API). Guard-the-call fix.

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Severity: Info
Status: new
Bucket: Base system — drivers
Confidence: certain
Pass: 2 · GLM 5.3 second pass
CVSS 3.1: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:N
CWE: CWE-476
File: sys/dev/drm/amd/display/dc/i2caux/dce110/aux_engine_dce110.c
Lines: 451-459
Area: dev
Discovered: 2026-09-24
Updated: 2026-09-24

Team triage

untriaged

priority: — · owner: —

PoC verification

untested

Status: untested
Reproduced: no
Impact: panic
Confidence: certain
Tested: 2026-09-24 15:17:54
Attempts: 0
Runtime: —
Code hash: —
Guest: —
Build cmd: —
Run cmd: —

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Fix verification

not_testable

Fix status: not_testable
Baseline reproduced: —
Patched reproduced: —
Confidence: certain
Tested: 2026-09-24 15:17:55
Runtime: —
Kernel: per-fix-DF-4861
fix.diff: findings/poc/DF-4861/fix.diff
Runner: df-bsd-reviewer

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PoC verification

Evidence pack

findings/poc/DF-4861 · 1 files

File	Type	Description	Size
verdict.json	file		994 B	view raw

Fix verification

not_testable

per-fix-DF-4861

Confirmed kernel references

Detail

Exploit chain

any future caller of dal_i2caux_configure_aux on DCE8-11.2 -> engine->funcs->configure == NULL -> kernel panic

Evidence (decisive lines)

findings/poc/DF-4861/ (this verdict)

Verdict

Latent dead-API hardening (zero callers tree-wide today): struct aux_engine_funcs declares .configure but the dce110 (and every i2caux) func table leaves it NULL via designated-initializer semantics, while the exported dal_i2caux_configure_aux() calls it unconditionally at i2caux.c:306 - a guaranteed NULL function-pointer panic the moment any future display-reconfig path uses the API (serves DCE 8.x-11.2 ASICs). No AMD GPU on guest. Guard-the-call (or stub) fix.