⬢ DragonFlyBSD Kernel Audit
DF-4215 / verdict.json
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{
  "finding_id": "DF-4215",
  "status": "untested",
  "reproduced": 0,
  "impact": "none",
  "confidence": "certain",
  "verdict": "construct() jumps to destruct() on any of six kzalloc failures, but destruct() unconditionally does dc_release_state(dc->current_state) (dc.c:521 \u2014 kref_put through NULL when current_state alloc at 615 failed) and derefs dc->ctx at 528/531/534/537 (NULL when the ctx alloc at 602 failed). A single OOM during amdgpu DC probe turns into a kernel NULL-deref panic instead of graceful Display Core failed to initialize.",
  "exploit_chain": "",
  "evidence": "findings/poc/DF-4215/VERDICT.md, findings/poc/DF-4215/env.txt (guest pciconf: no triggering hardware), findings/poc/DF-4215/fix.diff",
  "kernel_refs": [
    "sys/dev/drm/amd/display/dc/core/dc.c:521",
    "sys/dev/drm/amd/display/dc/core/dc.c:528",
    "sys/dev/drm/amd/display/dc/core/dc.c:602",
    "sys/dev/drm/amd/display/dc/core/dc.c:615",
    "sys/dev/drm/amd/display/dc/core/dc.c:686",
    "sys/dev/drm/amd/display/dc/core/dc.c:1103"
  ],
  "poc_changes": "no runnable PoC: hardware-gated path absent from the audit guest (env.txt)",
  "attempts": 0,
  "guest_uname": "DragonFly dfbsd 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64",
  "runtime_sec": 0,
  "guest_dirty": 0,
  "build_cmd": null,
  "run_cmd": null,
  "code_hash": null,
  "notes": "ASSERT/ASSERT_CRITICAL are WARN_ON-only in this tree (os_types.h:59-77) so nothing stops the deref.",
  "recommended_fix": "NULL-guard current_state and all dc->ctx derefs in destruct()",
  "fix_status": "not_testable",
  "fix_baseline_reproduced": 0,
  "fix_patched_reproduced": 0,
  "fix_verdict": "diff authored and git-apply-verified against the read-only sys/ tree; runtime fix validation impossible without the triggering hardware on the QEMU guest",
  "fix_evidence": "findings/poc/DF-4215/fix.diff (git apply --check passed)"
}