From 667296f14f39a2e36cf799b8fc6d534c9edad6df Mon Sep 17 00:00:00 2001
From: igneum-labs <337424239+igneum-labs@users.noreply.github.com>
Date: Wed, 7 Oct 2026 19:16:09 +0000
Subject: [PATCH] adv-cache-3: rank sampling fix, run-box.sh under the per-box
 sweep lock

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
---
 tools/attack/adv-cache-3/Cargo.lock  | 14 ++++++++++++++
 tools/attack/adv-cache-3/run-box.sh  | 17 +++++++++++++++++
 tools/attack/adv-cache-3/src/main.rs | 16 ++++++----------
 3 files changed, 37 insertions(+), 10 deletions(-)
 create mode 100644 tools/attack/adv-cache-3/Cargo.lock
 create mode 100755 tools/attack/adv-cache-3/run-box.sh

diff --git a/tools/attack/adv-cache-3/Cargo.lock b/tools/attack/adv-cache-3/Cargo.lock
new file mode 100644
index 000000000..61e969399
--- /dev/null
+++ b/tools/attack/adv-cache-3/Cargo.lock
@@ -0,0 +1,14 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "attack-adv-cache-3"
+version = "0.1.0"
+dependencies = [
+ "igneum-pow",
+]
+
+[[package]]
+name = "igneum-pow"
+version = "0.2.0"
diff --git a/tools/attack/adv-cache-3/run-box.sh b/tools/attack/adv-cache-3/run-box.sh
new file mode 100755
index 000000000..d86eab7a6
--- /dev/null
+++ b/tools/attack/adv-cache-3/run-box.sh
@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+# Start one adv-cache-3 sweep on a build box (run ON the box). Internal adversarial pass, not an independent review.
+#   run-box.sh <tag> <args...>
+# The binary is /srv/builds/_adv-cache-3/bin/adv-cache-3 (copied there after tools/build-remote.sh; the worktree mirror's
+# target dir is not used at run time). The log and pid file live under /srv/builds/_adv-cache-3/logs/<tag>.log{,.pid},
+# outside the worktree mirror, which build-remote.sh's source sync would wipe. The run takes the per-box sweep lock
+# (/srv/builds/_adv/locks/sweep.lock, coordinator's rule of 19:55 BST, 7 October 2026: one sweep per box at a time, up to 88
+# threads), runs at nice 10 on cores 8 to 95 (0 to 7 reserved), no SIGSTOP yield. Kill by pid file only: kill $(cat <pid>).
+set -euo pipefail
+tag="$1"; shift
+BIN=/srv/builds/_adv-cache-3/bin/adv-cache-3
+DIR=/srv/builds/_adv-cache-3/logs
+mkdir -p "$DIR"
+log="$DIR/$tag.log"
+nohup flock /srv/builds/_adv/locks/sweep.lock -c "nice -n 10 taskset -c 8-95 $BIN $* >> '$log' 2>&1" > /dev/null 2>&1 &
+echo $! > "$log.pid"
+echo "started $tag pid $(cat "$log.pid") log $log (waits for the sweep lock if held)"
diff --git a/tools/attack/adv-cache-3/src/main.rs b/tools/attack/adv-cache-3/src/main.rs
index 38a94248e..c376ae75b 100644
--- a/tools/attack/adv-cache-3/src/main.rs
+++ b/tools/attack/adv-cache-3/src/main.rs
@@ -281,10 +281,6 @@ fn key_of_day(d: u64) -> [u32; 8] {
     seed_words_from_bytes(&day_bytes(d))
 }
 
-fn real_blk(dr: u32, plant: Plant) -> Blk {
-    Blk::new(32, dr, plant != Plant::NoFeedforward)
-}
-
 /// The real block at w = 32, 6 double rounds, with the feed-forward, must equal the library's `chacha_block`;
 /// `core_inv` must invert `core` at every width used.
 fn self_test() {
@@ -581,7 +577,10 @@ fn cmd_skip(a: &Args) {
     let key = key_of_day(day);
     let nb = blk.bits();
     log!("skip: day {day} w {w} double rounds {dr} lines {n} segments {segs} plant {} threads {threads}; rotations {:?}", plant.name(), blk.rot);
-    let seg_of = |p: usize| -> u32 { if segs >= CACHE_SEGMENTS { p as u32 } else { ((p as u64 * 0x9E37) & 0xffff) as u32 } & blk.mask };
+    let seg_of = |p: usize| -> u32 {
+        let s = if segs >= CACHE_SEGMENTS { p as u32 } else { ((p as u64 * 0x9E37) & 0xffff) as u32 };
+        s & blk.mask
+    };
     let t0 = Instant::now();
 
     // (1) templates: match counts per template per j, and the chance expectation
@@ -661,11 +660,8 @@ fn cmd_skip(a: &Args) {
     // (2) the GF(2) rank test on (x_j, line_j) and (line_{j-1}, line_j)
     let samples = 4096usize;
     let js_test: Vec<usize> = [1usize, 2, n / 2, n - 1].into_iter().filter(|&j| j >= 1 && j < n).collect();
-    let mut sample_lines: Vec<(Vec<[u32; 16]>, Vec<[u32; 16]>)> = Vec::new();
-    for p in 0..(samples / n.max(1) + 1).max(samples / 63 + 1) {
-        let s = seg_of(p);
-        sample_lines.push(chain(&blk, &key, s, n, plant));
-    }
+    // one chain per sample segment, so the per-j test has `samples` rows at every j (the first run had 66)
+    let sample_lines: Vec<(Vec<[u32; 16]>, Vec<[u32; 16]>)> = par(threads, samples, |_, lo, hi| (lo..hi).map(|p| chain(&blk, &key, seg_of(p), n, plant)).collect::<Vec<_>>()).into_iter().flatten().collect();
     for &j in &js_test {
         let mut g_x = Gf2::new();
         let mut g_p = Gf2::new();