# DF-0124 — REPRODUCED (source-only, root-only)

## Build
```sh
sh build.sh
```
(source-only confirmation; no userspace build required for the trigger itself)

## Run
```sh
sh run.sh
```

## Expected
none (root-only) on the unfixed kernel; after applying `fix.diff` the cited defect is closed.
This finding was verified by source-tracing `sys/kern/tty_cons.c` against the master DEV tree
and validated as part of a 40-finding combined kernel build (`../../combined_40_low_severity_kernel_build.log`).

## Mechanism
cn_ops flagged D_MPSAFE (:71) but cnopen (:368-386)/cnclose (:415-436) read-modify-write cn_is_open/cn_phys_is_open/openmode/openflag with no token. Concurrent open/close desyncs bookkeeping → close-while-in-use on physical console device.