=== FIXED kernel run (#1, 2026-07-14 14:18:23 UTC build) ===
Guest: DragonFly 6.5-DEVELOPMENT #1: Tue Jul 14 14:18:23 UTC 2026

Command (as root):
  sysctl hw.cpu_topology_phys_ids=0
  sysctl hw.cpu_topology_core_ids=2000
  sysctl hw.cpu_topology_core_ids=0

Output:
[*] attempt variant A (phys_ids=0):
sysctl: oid 'hw.cpu_topology_phys_ids' is read only
rc=1
[*] attempt variant B (core_ids=2000):
sysctl: oid 'hw.cpu_topology_core_ids' is read only
rc=1
[*] attempt variant C (core_ids=0):
sysctl: oid 'hw.cpu_topology_core_ids' is read only
rc=1
---ssh rc=0---
up

PoC script (sh /root/poc.sh):
[*] before:
hw.cpu_topology_phys_ids: 1
hw.cpu_topology_core_ids: 6
hw.cpu_topology_ht_ids: 1
sysctl: oid 'hw.cpu_topology_phys_ids' is read only
POC_EXIT=1
--- guest stays UP, no panic ---

RESULT: FIX VERIFIED. sysctl write rejected (read-only); no divide-by-zero; guest survives.