# DF-1791 — 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/misc/puc/puc.c:446`.

## Mechanism
puc_config_superio calls puc_config_win877(sc->sc_bar_mappings[0].res) without NULL guard; BAR 0 alloc loop tolerates failure leaving res==NULL, rman derefs NULL tag/handle.

## Fix
Guard res==NULL before calling puc_config_win877.

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 device driver 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.