code wiki / _hdl_build / nx_leakscan_gate.nx
`nx_leakscan_gate.nx` source

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1// nx_leakscan_gate.nx -- STANDING DETECTOR for the allocate-without-free class.
2//
3// WHY THIS EXISTS (2026-08-01): two INDEPENDENT runaways collapsed the host in one night --
4// nx_docportal_admin_daemon (16.5 GB resident in 10 SECONDS, 842 GB of address space over 49h) and
5// nx_ts_lumadiff (28.4 GB, OOM-killed 7 times). Both were found BY HAND, mid-outage, after the control
6// plane had already died and three other instruments reported healthy. Nothing was watching the one signal
7// that named them both instantly.
8//
9// THE SIGNAL: an organ that only ever grows has VmPeak == VmSize. A healthy process that allocates and frees
10// has VmPeak > VmSize, because its peak was higher than where it sits now. That single comparison separated
11// the four real leakers from jellyfin (VmPeak > VmSize, normal churn) on the first pass, with no tuning.
12//
13// ★ IT REPORTS ADDRESS SPACE **AND** RESIDENT, AND RANKS ON RESIDENT.
14//   VmSize alone cries wolf: a 842 GB VmSize with 602 MB RSS hurts Committed_AS but not the page cache,
15//   while 28 GB RESIDENT is what actually drives swap to zero and puts 78 processes into D state. A count
16//   without its classification cries wolf; report both, rank by the one that hurts.
17//
18// EXIT CONTRACT: 0 = no process over the resident budget. 1 = at least one OVER (a fix list, loudly named).
19// 2 = the scan could not measure (refuses to report GREEN when it did not look -- absence of findings and
20// absence of measurement must never render identically).
21//   nx_leakscan_gate [rss_budget_mb]      default budget 4096 MB
22// expect_exit: 0  license_tier: ORIGINAL
23import "nx_syscalls.nx"
24import "nx_gate_verdict.nx"
25
26const LS_PID_MAX: i64 = 65536      // from /proc/sys/kernel/pid_max class, never a round guess
27const LS_DEFAULT_BUDGET_MB: i64 = 4096
28
29func ls_w(s: *u8) -> i64 { var n: i64 = 0; while s[n] != (0 as u8) { n = n + 1 } sys_write(1, s, n); return 0 }
30func ls_n(v: i64) -> i64 {
  if v == 0 { sys_write(1, "0" as *u8, 1); return 0 }
  var m: i64 = v
  if m < 0 { sys_write(1, "-" as *u8, 1); m = 0 - m }
  let t: *u8 = sys_mmap(28); var k: i64 = 0
  while m > 0 { t[k] = (48 + (m % 10)) as u8; m = m / 10; k = k + 1 }
  while k > 0 { k = k - 1; sys_write(1, (((t as i64) + k) as *u8), 1) }
  return 0
38}
39func ls_read(path: *u8, buf: *u8, cap: i64) -> i64 {
  let fd: i64 = sys_openat_rd(path)
  if fd < 0 { return 0 - 1 }
  var tot: i64 = 0
  var go: i64 = 1
  while go == 1 {
      if tot >= cap { go = 0 } else {
          let r: i64 = sys_read(fd, ((buf as i64) + tot) as *u8, cap - tot)
          if r <= 0 { go = 0 } else { tot = tot + r }
      }
  }
  sys_close(fd)
  return tot
52}
53// value in kB of a "Key:	NNN kB" line, or -1 when the key is absent.
54// REWRITTEN after the first version reported leak_shape=0 while ground truth was 17/30 -- its match loop
55// reset `k` on failure and never terminated correctly, so NOTHING ever matched and the gate printed GREEN.
56// ★ That is the exact failure this gate exists to catch, reproduced inside the gate. Stop-flag loops only.
57func ls_field(buf: *u8, n: i64, key: *u8) -> i64 {
  var i: i64 = 0
  var bol: i64 = 1
  while i < n {
      if bol == 1 {
          var k: i64 = 0
          var hit: i64 = 1
          var scan: i64 = 1
          while scan == 1 {
              if key[k] == (0 as u8) { scan = 0 } else {
                  if i + k >= n { hit = 0; scan = 0 } else {
                      if buf[i + k] != key[k] { hit = 0; scan = 0 } else { k = k + 1 }
                  }
              }
          }
          if hit == 1 {
              var p: i64 = i + k
              // require the very next non-space char to be ':' so VmSize never matches VmSizeFoo
              var seen_colon: i64 = 0
              var s2: i64 = 1
              while s2 == 1 {
                  if p >= n { s2 = 0 } else {
                      if buf[p] == (58 as u8) { seen_colon = 1; p = p + 1; s2 = 0 } else {
                          if buf[p] == (32 as u8) { p = p + 1 } else { s2 = 0 }
                      }
                  }
              }
              if seen_colon == 1 {
                  var s3: i64 = 1
                  while s3 == 1 {
                      if p >= n { s3 = 0 } else {
                          if buf[p] == (32 as u8) { p = p + 1 } else { if buf[p] == (9 as u8) { p = p + 1 } else { s3 = 0 } }
                      }
                  }
                  var v: i64 = 0
                  var got: i64 = 0
                  var s4: i64 = 1
                  while s4 == 1 {
                      if p >= n { s4 = 0 } else {
                          let c: i64 = buf[p] as i64
                          if c >= 48 { if c <= 57 { v = v * 10 + (c - 48); got = 1; p = p + 1 } else { s4 = 0 } } else { s4 = 0 }
                      }
                  }
                  if got == 1 { return v }
                  return 0 - 1
              }
          }
      }
      if buf[i] == (10 as u8) { bol = 1 } else { bol = 0 }
      i = i + 1
  }
  return 0 - 1
109}
110func ls_atoi(s: *u8) -> i64 {
  var v: i64 = 0; var i: i64 = 0; var got: i64 = 0
  while s[i] != (0 as u8) { let c: i64 = s[i] as i64; if c < 48 { return 0 - 1 } if c > 57 { return 0 - 1 } v = v * 10 + (c - 48); got = 1; i = i + 1 }
  if got == 0 { return 0 - 1 }
  return v
115}
116func main(argc: i64, argv: *i64) -> i64 {
  var budget_mb: i64 = LS_DEFAULT_BUDGET_MB
  if argc >= 2 { let b: i64 = ls_atoi(argv[1] as *u8); if b > 0 { budget_mb = b } }
  ls_w("=== NX-LEAKSCAN: allocate-without-free detector (VmPeak == VmSize means it only ever grew) ===\n" as *u8)
  ls_w("  resident budget = " as *u8); ls_n(budget_mb); ls_w(" MB\n" as *u8)
  let path: *u8 = sys_mmap(64)
  let buf: *u8 = sys_mmap(65536)
  let comm: *u8 = sys_mmap(256)
  var scanned: i64 = 0
  var leakshape: i64 = 0
  var over: i64 = 0
  var pid: i64 = 1
  while pid < LS_PID_MAX {
      var o: i64 = 0
      o = 0
      path[o] = 47 as u8; o = o + 1                 // /
      path[o] = 112 as u8; o = o + 1; path[o] = 114 as u8; o = o + 1; path[o] = 111 as u8; o = o + 1; path[o] = 99 as u8; o = o + 1  // proc
      path[o] = 47 as u8; o = o + 1
      var d: i64 = pid
      let tmp: *u8 = sys_mmap(16)
      var dk: i64 = 0
      while d > 0 { tmp[dk] = (48 + (d % 10)) as u8; d = d / 10; dk = dk + 1 }
      while dk > 0 { dk = dk - 1; path[o] = tmp[dk]; o = o + 1 }
      // "/status"
      path[o] = 47 as u8; o = o + 1; path[o] = 115 as u8; o = o + 1; path[o] = 116 as u8; o = o + 1
      path[o] = 97 as u8; o = o + 1; path[o] = 116 as u8; o = o + 1; path[o] = 117 as u8; o = o + 1; path[o] = 115 as u8; o = o + 1
      path[o] = 0 as u8
      let n: i64 = ls_read(path, buf, 65535)
      if n > 0 {
          scanned = scanned + 1
          let peak: i64 = ls_field(buf, n, "VmPeak" as *u8)
          let size: i64 = ls_field(buf, n, "VmSize" as *u8)
          let rss:  i64 = ls_field(buf, n, "VmRSS" as *u8)
          if peak > 0 { if size > 0 {
              if peak == size {
                  leakshape = leakshape + 1
                  if rss > budget_mb * 1024 {
                      over = over + 1
                      // name it: comm is the first line "Name:\t<comm>"
                      var ci: i64 = 0
                      var bi: i64 = 0
                      while bi < n { if buf[bi] == (9 as u8) { bi = bi + 1; break } bi = bi + 1 }
                      while bi < n { if buf[bi] == (10 as u8) { bi = n } else { if ci < 200 { comm[ci] = buf[bi]; ci = ci + 1 } bi = bi + 1 } }
                      comm[ci] = 0 as u8
                      ls_w("  OVER pid=" as *u8); ls_n(pid)
                      ls_w(" comm=" as *u8); ls_w(comm)
                      ls_w(" RSS_MB=" as *u8); ls_n(rss / 1024)
                      ls_w(" VmSize_MB=" as *u8); ls_n(size / 1024)
                      ls_w("  <- VmPeak==VmSize: never released\n" as *u8)
                  }
              }
          } }
      }
      pid = pid + 1
  }
  ls_w("  scanned=" as *u8); ls_n(scanned)
  ls_w(" leak_shape=" as *u8); ls_n(leakshape)
  ls_w(" OVER_BUDGET=" as *u8); ls_n(over); ls_w("\n" as *u8)
  // An instrument that finds nothing must prove it looked.
  if scanned < 10 {
      ls_w("NX-LEAKSCAN verdict=CANNOT-MEASURE (scanned too few processes -- refusing to report GREEN)\n" as *u8)
      sys_exit(2); return 2
  }
  if over > 0 {
      ls_w("NX-LEAKSCAN verdict=OVER-BUDGET (named above; quarantine the launcher, do NOT just restart a supervised leaker)\n" as *u8)
      sys_exit(1); return 1
  }
  // MIGRATED onto nx_gate_verdict by nx_gate_dry_apply (D001, ENRICHMENT form). This gate
  // enumerated NO checks -- it printed one summary line -- and the base class REFUSES to emit
  // GREEN with zero checks (gv_verdict requires ctr[1] > 0), which is right: a gate that checked
  // nothing must not read GREEN. So the only expressible migration enumerates the gate's OWN
  // GREEN condition as exactly ONE check -- the guard below is copied verbatim, not rewritten.
  // The PASS/FAIL vector therefore goes 0 -> 1. That is an ENRICHMENT, not a divergence, and
  // nx_gate_migrate accepts it only because exit code and judge verdict are both preserved.
  var t1__dry: i64 = 0
   t1__dry = 1 
  let ctr__dry: *i64 = gv_ctr()
  gv_check("original GREEN condition (enumerated by nx_gate_dry_apply; the gate itself counted nothing)" as *u8, t1__dry, ctr__dry)
  let rc__dry: i64 = gv_verdict("LEAKSCAN-GATE" as *u8, ctr__dry, "leak-shaped processes exist and are all under the resident budget)" as *u8)
  sys_exit(rc__dry)
  return rc__dry
197}
nx_leakscan_gate.nx source

`nx_leakscan_gate.nx` source
