# DF-1770 — Verdict

**Severity:** Low
**Status:** REPRODUCED (source-only confirmation — driver/HW-gated, not runtime-triggered on QEMU guest)
**Impact:** panic
**Confidence:** certain

## Verdict
REPRODUCED. The cited bug is confirmed real in the audited source at `sys/dev/drm/i915/intel_dsi_vbt.c:134-140`.

## Mechanism
mipi_exec_send_packet derefs intel_dsi->dsi_hosts[port] without NULL check; single-link PORT_A panel has dsi_hosts[PORT_C]==NULL, crafted VBT SEND_PKT triggers NULL deref panic.

## Fix
Validate dsi_hosts[port]!=NULL before deref.

The full git-apply-able diff is in `fix.diff`.

## Build validation
fix.diff applies cleanly and compiles with `-Werror` as part of the batch module build
(all 51 fixes applied to /usr/src, kernel+modules built).

## Notes
Source-only confirmation: this finding is in a GPU/display code path that requires
specific hardware not present in the QEMU guest. The bug is confirmed by source tracing
(cited path:line verified against sys/), and the fix compiles clean. No runtime trigger
was attempted as the relevant device/module is HW-gated.