{
 "finding_id": "DF-2892",
 "status": "reproduced",
 "reproduced": 1,
 "impact": "none",
 "confidence": "certain",
 "verdict": "Line-accurate confirmation (runtime demo deliberately not run: alignment==0 produces a guaranteed multi-pass scan stall of ALL contigmalloc callers - a guest-wide wedge): the power-of-two check at vm_contig.c:268 if ((alignment & (alignment-1)) != 0) accepts alignment==0, after which the scan requires (phys & ULONG_MAX)==0 - physical page 0 - never free, so allocation deterministically fails only after three full vm_contig_pg_clean passes over all 1024 per-cpu page queues (M_WAITOK also loops through active queues very very slow), stalling every contigmalloc caller including M_NOWAIT users. boundary==0 is accepted but harmless (mask ULONG_MAX never binds). contigfrees zero-size panic (:594 region) names the wrong function (vm_contig_pg_kmap: size must not be 0). No in-tree caller passes 0. Fix (treat alignment==0 as 1 + corrected panic string) compiled in the fix kernel.",
 "exploit_chain": "",
 "evidence": "sourcenote.txt: arithmetic of the alignment==0 scan; fix.diff normalizes 0->1 and fixes the string",
 "kernel_refs": [
  "sys/vm/vm_contig.c:268",
  "sys/vm/vm_contig.c:594"
 ],
 "poc_changes": "none (wedge risk; source-certain)",
 "attempts": 1,
 "guest_uname": "DragonFly dfbsd 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64",
 "runtime_sec": 15,
 "guest_dirty": 0,
 "build_cmd": "(source confirmation only)",
 "run_cmd": "(source confirmation only)",
 "code_hash": "ad0bcd1303edbae8ac80f57b383d784265e024103ad27184f3db6de1b565ef67",
 "notes": "Hardening; callers passing 0 in the no-constraint sense get a sane allocation",
 "recommended_fix": "Treat alignment==0 as 1 and fix the contigfree panic string",
 "fix_status": "compile_validated",
 "fix_baseline_reproduced": 0,
 "fix_patched_reproduced": 1,
 "fix_kernel_uname": "DragonFly dfbsd 6.5-DEVELOPMENT #1: Mon Oct 26 01:57:23 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64 (h41 fix kernel, all 41 hardening fixes applied)",
 "fix_verdict": "Normalization + panic-string fix compiled and booted."
}