`parallel/test-snapshot-reproducible` fails when ASLR is enabled

test/parallel/test-snapshot-reproducible.js から始め、特に 47 行目の assertion を確認します。Linux ASLR を 1 または 2 に設定した状態で ./configure && make を使って再現し、その後、ASLR を無効にした場合に生成される snapshot と比較します。失敗が修正されるか、明確な次のステップを伴う、文書化された V8 固有または環境固有の原因に絞り込まれれば完了です。

Testing main on linux:

# sysctl -w kernel.randomize_va_space=2
$ ./configure && make && ./node test/parallel/test-snapshot-reproducible.js
node:internal/assert/utils:146
  throw error;
  ^

AssertionError [ERR_ASSERTION]: Expected values to be strictly deep-equal:
+ actual - expected
... Skipped lines

  [
    '#include <cstddef>',
    '#include "env.h"',
    '#include "node_snapshot_builder.h"',
    '#include "v8.h"',
...
    'namespace node {',
+   'static const char v8_snapshot_blob_data[] = {4,0,0,0,1,0,0,0,43,108,-20,-8,-43,-25,-94,-55,49,52,46,54,46,50,48,50,46,51,52,45,110,111,100,101,46,50,49,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,  // 0',
-   'static const char v8_snapshot_blob_data[] = {4,0,0,0,1,0,0,0,-99,103,75,7,-43,-25,-94,-55,49,52,46,54,46,50,48,50,46,51,52,45,110,111,100,101,46,50,49,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,  // 0',
    '0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,16,10,23,0,64,8,25,0,72,114,29,0,8,107,30,0,-120,98,31,0,-40,88,32,0,-85,6,-34,-64,-96,9,23,0,-83,24,96,0,0,0,0,86,0,0,0,96,0,0,0,0,  // 1',
    '0,0,0,0,96,0,0,0,0,0,0,0,0,96,0,0,0,0,-53,1,0,0,96,0,0,0,0,-84,1,0,0,96,0,0,0,0,-64,2,0,0,96,0,0,0,0,0,0,0,0,96,0,0,0,0,-30,0,0,0,11,5,24,98,0,2,  // 2',
    '5,24,34,1,2,5,24,-30,1,2,5,24,-94,2,2,5,24,98,3,2,5,24,34,4,2,5,24,-30,4,2,5,24,-94,5,2,5,24,98,6,2,5,24,34,7,2,5,24,-30,7,2,5,24,-94,8,2,5,24,98,9,2,1,76,7,101,  // 3',
    '15,69,64,97,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,64,98,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,64,96,0,0,0,0,0,0,0,0,7,-123,2,64,96,0,0,0,  // 4',
    '0,8,0,0,0,-127,0,91,64,1,20,83,69,97,0,0,0,0,96,0,0,0,0,0,0,0,1,0,0,0,93,1,20,83,69,97,0,0,0,0,96,0,0,0,0,0,0,0,1,0,0,0,93,1,20,83,69,97,0,0,0,0,96,0,  // 5',
...
    '26,-87,22,26,-11,27,26,93,28,26,101,28,26,105,34,26,69,37,26,73,37,26,77,37,26,81,37,26,85,37,26,89,37,26,93,37,26,97,37,26,101,37,26,-87,43,26,-83,43,26,-71,43,1,20,86,98,0,0,0,0,3,0,0,0,0,  // 42996',
+   '0,0,0,1,0,0,0,0,0,0,0,14,0,0,0,64,91,31,0,6,-71,2,5,24,66,66,4,4,8,95,4,73,33,11,15,0,-3,15,0,8,6,0,0,-3,15,4,96,6,-86,-127,-107,44,127,0,0,24,0,0,0,0,0,0,0,47,  // 42997',
+   '0,0,0,0,0,0,0,0,-107,26,0,8,8,0,0,-107,26,4,64,8,-102,-74,95,5,0,0,0,16,0,0,0,0,0,0,0,0,-99,39,0,8,2,0,0,-99,39,4,-64,2,-102,-74,95,5,0,0,0,48,0,0,0,0,0,0,0,51,  // 42998',
+   '0,0,0,0,0,0,0,52,0,0,0,0,0,0,0,53,0,0,0,0,0,0,0,54,0,0,0,0,0,0,0,0,-67,49,0,8,7,0,0,-67,49,4,64,7,-102,-74,95,5,0,0,0,16,0,0,0,0,0,0,0,0,-123,56,0,8,  // 42999',
+   '9,0,0,-123,56,4,64,9,-101,-74,95,5,0,0,0,16,0,0,0,0,0,0,0,0,-59,79,-128,32,32,0,0,0,0,0,0,0,0,-59,79,-108,32,37,0,0,0,0,0,0,0,0,-59,79,-104,32,38,0,0,0,0,0,0,0,0,-59,  // 43000',
+   '79,-100,32,39,0,0,0,0,0,0,0,0,-91,108,0,8,3,0,0,-91,108,4,96,3,-86,-127,-107,44,127,0,0,24,0,0,0,0,0,0,0,43,0,0,0,0,0,0,0,0,-75,108,0,8,0,0,0,-75,108,4,96,0,-102,-74,95,5,  // 43001',
+   '0,0,0,24,0,0,0,0,0,0,0,45,0,0,0,0,0,0,0,0,-67,108,0,8,5,0,0,-67,108,4,64,5,114,5,54,-2,85,0,0,16,0,0,0,0,0,0,0,0,-51,108,0,8,1,0,0,-51,108,4,96,1,-102,-74,95,5,  // 43002',
-   '0,0,0,1,0,0,0,0,0,0,0,14,0,0,0,64,91,31,0,6,-71,2,5,24,66,66,4,4,8,95,4,73,33,11,15,0,-3,15,0,8,6,0,0,-3,15,4,96,6,-86,33,30,70,127,0,0,24,0,0,0,0,0,0,0,47,  // 42997',
-   '0,0,0,0,0,0,0,0,-107,26,0,8,8,0,0,-107,26,4,64,8,36,-106,100,5,0,0,0,16,0,0,0,0,0,0,0,0,-99,39,0,8,2,0,0,-99,39,4,-64,2,36,-106,100,5,0,0,0,48,0,0,0,0,0,0,0,51,  // 42998',
-   '0,0,0,0,0,0,0,52,0,0,0,0,0,0,0,53,0,0,0,0,0,0,0,54,0,0,0,0,0,0,0,0,-67,49,0,8,7,0,0,-67,49,4,64,7,36,-106,100,5,0,0,0,16,0,0,0,0,0,0,0,0,-123,56,0,8,  // 42999',
-   '9,0,0,-123,56,4,64,9,36,-106,100,5,0,0,0,16,0,0,0,0,0,0,0,0,-59,79,-128,32,32,0,0,0,0,0,0,0,0,-59,79,-108,32,37,0,0,0,0,0,0,0,0,-59,79,-104,32,38,0,0,0,0,0,0,0,0,-59,  // 43000',
-   '79,-100,32,39,0,0,0,0,0,0,0,0,-91,108,0,8,3,0,0,-91,108,4,96,3,-86,33,30,70,127,0,0,24,0,0,0,0,0,0,0,43,0,0,0,0,0,0,0,0,-75,108,0,8,0,0,0,-75,108,4,96,0,36,-106,100,5,  // 43001',
-   '0,0,0,24,0,0,0,0,0,0,0,45,0,0,0,0,0,0,0,0,-67,108,0,8,5,0,0,-67,108,4,64,5,-52,-33,6,76,86,0,0,16,0,0,0,0,0,0,0,0,-51,108,0,8,1,0,0,-51,108,4,96,1,36,-106,100,5,  // 43002',
    '0,0,0,24,0,0,0,0,0,0,0,57,0,0,0,0,0,0,0,11,10,10,10,10',
    '};',
    'static const int v8_snapshot_blob_size = 2752216;',
    'static const uint8_t vm_cache_data[] = {171,6,222,192,82,189,255,151,217,50,0,32,97,100,152,163,213,231,162,201,96,21,0,0,0,0,0,0,0,0,0,0,1,36,81,3,109,1,7,196,96,0,0,0,0,151,2,0,0,1,8,7,33,15,4,4,33,3,112,7,181,1,122,0,  // 0',
    '0,0,0,205,0,0,0,2,4,6,0,179,5,156,36,26,100,22,64,26,76,26,68,26,64,23,220,3,14,0,22,203,2,22,80,26,60,22,112,27,216,3,14,0,22,104,22,203,2,26,124,27,168,9,14,0,22,143,7,26,68,26,76,26,  // 1',

    at Object.<anonymous> (/node/test/parallel/test-snapshot-reproducible.js:47:8)
    at Module._compile (node:internal/modules/cjs/loader:1947:14)
    at Object..js (node:internal/modules/cjs/loader:2087:10)
    at Module.load (node:internal/modules/cjs/loader:1669:32)
    at Module._load (node:internal/modules/cjs/loader:1450:12)
    at wrapModuleLoad (node:internal/modules/cjs/loader:260:19)
    at Module.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:154:5)
    at node:internal/main/run_main_module:33:47 {
  generatedMessage: true,
  code: 'ERR_ASSERTION',
  actual: [ <skipped> ],
  expected: [ <skipped> ],
  operator: 'deepStrictEqual',
  diff: 'simple'
}

Node.js v27.0.0-pre

Reproducible locally with gcc 15.3.0 and 16.1.1.
The byteranges that differ are randomized so the exact bytes are different each time. Everything else seems to be consistent.
Completely disabling ASLR (setting kernel/randomize_va_space to 0) makes the test pass. Conservative ASLR (1) still breaks it.

Not exactly sure when this started (maybe some of v8 upgrades?) nor whether it can be fixed (maybe on v8 side?) nor what else causes this (test passes on CI so i assume there's additional factor to it).