openclaw - 💡(How to fix) Fix bug(gateway): SIGILL crash on CPUs without AVX2 (Celeron N5095A) — works with --jitless

Bug: Gateway crashes with SIGILL (Illegal Instruction) on CPUs without AVX2 — code=dumped, status=4/ILL

Summary

OpenClaw Gateway crashes consistently during startup with SIGILL (signal 4, Illegal Instruction) on CPUs that lack AVX2 support. The crash happens right after all feishu WebSocket clients connect, before any messages are processed.

Running with --jitless (disables V8 JIT) resolves the crash.

Environment

Behavior

• Gateway starts successfully: config loads, plugins initialize, HTTP server listens
• ALL feishu WebSocket clients connect successfully (bot identity resolved, WebSocket client started)
• ~1 second after the last WebSocket client connects, the process crashes: code=dumped, status=4/ILL (SIGILL)
• systemd restart loop: restarts immediately, crashes again (exhausted after 5 attempts with default StartLimitBurst)
• No error messages in gateway logs before the crash
• dmesg shows no kernel-level fault
• Apport crash dump confirms: Signal: 4, SignalName: SIGILL

Root Cause

The Intel Celeron N5095A (Jasper Lake) is a low-power CPU that lacks AVX2 support (confirmed via /proc/cpuinfo flags).

Node.js v24.15.0's V8 TurboFan JIT compiler generates code using AVX2 (or other advanced SIMD) instructions for hot paths. When this JIT-compiled code is executed on a CPU without AVX2 support, the processor raises SIGILL.

strace Analysis

clone3 → child process / worker thread created
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_DUMPED, si_status=SIGILL} ---
kill(parent_pid, SIGILL)  ← process terminates itself after worker crash

The crash originates in a Node.js worker thread (not an external process — no execve calls observed), where the V8 JIT-compiled code contains instructions unsupported by the target CPU.

Fix

Running with --jitless disables V8's JIT compiler entirely:

/usr/bin/node --jitless /path/to/openclaw/dist/index.js gateway --port 18789

This resolves the crash completely. The gateway starts up, all feishu instances connect, and message processing works normally.

Impact of --jitless

• LLM API calls (model inference) are unaffected — they run on provider servers
• Local plugin tasks (file processing, canvas/skia rendering) may be 10-30% slower due to interpreter-only execution
• No functional limitations observed in testing

Additional Notes

This may affect other users running OpenClaw on low-power or older x86_64 hardware:

• Intel: Celeron (pre-2021), Atom, older Pentium
• AMD: older CPUs without AVX2 support

It may also affect users running Node.js from NodeSource on these platforms.

Workarounds

1. --jitless flag (proven, simple): Add to systemd ExecStart, preferably via a drop-in to survive openclaw gateway install:

   mkdir -p ~/.config/systemd/user/openclaw-gateway.service.d
   # create drop-in with --jitless
   systemctl --user daemon-reload

2. Node.js downgrade (untested): Downgrade to an older Node.js LTS version (e.g., v22.x) whose V8 JIT may not emit the problematic instructions.

3. Source-compile Node.js (maintenance-heavy):

   ./configure --without-avx2

Feature Request (if appropriate)

Allow Gateway service template to honor NODE_OPTIONS environment variable from OpenClaw config, so users with CPU compatibility issues can apply flags like --jitless without modifying systemd service files.