WasmGC cumulative array allocations crash Node.js process with FATAL ERROR instead of trapping

Version

24.2.0

Platform

Linux unknown387c76016c42.lan 6.19.14-108.fc42.x86_64 #1 SMP PREEMPT_DYNAMIC Thu May 21 18:06:59 UTC 2026 x86_64 GNU/Linux

Subsystem

No response

What steps will reproduce the bug?

1. Save the attached exhaust.wat file
2. Compile: wasm-tools parse exhaust.wat -o exhaust.wasm
3. Run: node test.js
4. Process crashes with FATAL ERROR + core dump

exhaust.wat:

(module
  (type $arr (array (mut i64)))
  (type $holder (array (mut (ref null $arr))))

  (func (export "exhaust") (param $count i32)
    (local $h (ref $holder))
    (local $i i32)

    ;; parent array to hold all refs (prevents GC collection)
    (array.new_default $holder (local.get $count))
    (local.set $h)

    (loop $loop
      ;; allocate ~1MB array (131072 x 8 bytes)
      (local.get $h)
      (local.get $i)
      (array.new_default $arr (i32.const 131072))
      (array.set $holder)

      ;; i++
      (local.get $i)
      (i32.const 1)
      (i32.add)
      (local.set $i)

      ;; loop while i < count
      (local.get $i)
      (local.get $count)
      (i32.lt_u)
      (br_if $loop)
    )
  )
)

test.js:

const fs = require('fs');
(async () => {
  const mod = await WebAssembly.compile(fs.readFileSync('exhaust.wasm'));
  const inst = await WebAssembly.instantiate(mod);
  console.log('Allocating 10,000 x 1MB...');
  inst.exports.exhaust(10000);
  console.log('Survived (should not reach here)');
})();

How often does it reproduce? Is there a required condition?

Fully reproducible.

What is the expected behavior? Why is that the expected behavior?

The Wasm module should trap or throw a catchable JavaScript error on GC allocation failure, not crash the process with abort(). Linear memory already handles exhaustion gracefully (memory.grow returns -1), and the WasmGC spec allows implementations to "terminate that computation and report an embedder-specific error" on resource exhaustion.

What do you see instead?

Exit code: 134

Allocating 10,000 x 1MB...

<--- Last few GCs --->

[132127:0x365f6000]     1871 ms: Mark-Compact 4062.8 (4207.1) -> 4062.1 (4207.1) MB, pooled: 1 MB, 5.87 / 0.00 ms  (average mu = 0.944, current mu = 0.848) allocation failure; scavenge might not succeed
[132127:0x365f6000]     1891 ms: Mark-Compact 4095.1 (4240.3) -> 4095.0 (4240.3) MB, pooled: 1 MB, 7.87 / 0.00 ms  (average mu = 0.894, current mu = 0.604) allocation failure; scavenge might not succeed

FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory
----- Native stack trace -----

 1: 0xf1eeef node::OOMErrorHandler(char const*, v8::OOMDetails const&) [node]
 2: 0x1351da0 v8::Utils::ReportOOMFailure(v8::internal::Isolate*, char const*, v8::OOMDetails const&) [node]
 3: 0x1351e8f v8::internal::V8::FatalProcessOutOfMemory(v8::internal::Isolate*, char const*, v8::OOMDetails const&) [node]
 4: 0x15e8505  [node]
 5: 0x15f968c v8::internal::Heap::CollectGarbage(v8::internal::AllocationSpace, v8::internal::GarbageCollectionReason, v8::GCCallbackFlags) [node]
 6: 0x15cf2f3 v8::internal::HeapAllocator::AllocateRawWithRetryOrFailSlowPath(int, v8::internal::AllocationType, v8::internal::AllocationOrigin, v8::internal::AllocationAlignment) [node]
 7: 0x15a5770 v8::internal::Factory::NewFillerObject(int, v8::internal::AllocationAlignment, v8::internal::AllocationType, v8::internal::AllocationOrigin) [node]
 8: 0x1a98558 v8::internal::Runtime_AllocateInYoungGeneration(int, unsigned long*, v8::internal::Isolate*) [node]
 9: 0x21a1989  [node]
[1]    132127 IOT instruction (core dumped)  node test.js

Additional information

Bug found during the investigation on https://github.com/bytecodealliance/endive/issues/102

Reproduce the failure with exhaust.wat, wasm-tools parse, and test.js, then inspect the WasmGC allocation path around the V8 heap and OOM stack shown in the report. Trace how allocation failure is reported to Node.js and verify that the reproduction terminates with a catchable error or trap instead of aborting the process.