language_server_linux_x64 memory leak causes system OOM on Remote SSH (60GB+ RSS)

[lincos-sergey]

Bug: language_server_linux_x64 memory leak causes system OOM on Remote SSH

Environment

• Windsurf version: Latest (Feb 2026)
• Connection: Remote SSH to AWS EC2
• Remote OS: Ubuntu 24.04 LTS (kernel 6.14.0-1018-aws)
• Remote Instance: AWS r7i.2xlarge (8 vCPU, 64 GB RAM, 16 GB swap)
• Local OS: macOS
• Language server binary: language_server_linux_x64 (Go binary, located in .windsurf-server/bin/.../extensions/windsurf/bin/)

Description

When using Windsurf via Remote SSH, the language_server_linux_x64 process has an unbounded memory leak that grows from ~3.5 GB at startup to 60+ GB within hours, consuming all available RAM and swap, ultimately freezing the entire remote system.

This has been consistently reproducible across multiple days (Feb 11–15, 2026), happening every time the IDE is used for a few hours.

Reproduction

1. Connect Windsurf to a remote Linux machine via Remote SSH
2. Open a workspace and use Cascade normally
3. After several hours of usage, language_server_linux_x64 will have consumed all available RAM
4. The remote machine becomes completely unresponsive (hard freeze, requires power cycle)

Diagnostic Evidence

A custom system monitor service logging every 60 seconds captured the memory growth leading up to the crash:

TIME            language_server RSS    System Memory Used    Load Average
─────────────   ──────────────────     ──────────────────    ────────────
21:11 UTC       33 GB (51% of RAM)     38 GB                 1,038
21:12 UTC       42 GB (66% of RAM)     47 GB                   877
21:13 UTC       58 GB (89% of RAM)     62 GB                   830
21:14 UTC       59 GB (91% of RAM)     62 GB                   838
21:15 UTC       60 GB (92% of RAM)     62 GB                   781
21:17 UTC       60 GB (93% of RAM)     62 GB (swap: 3.3 GB)    702
  ...           SYSTEM FREEZE — required instance stop/start to recover

Key observations:

• Only language_server_linux_x64 grows — all other Windsurf node processes remain under 2 GB
• Memory growth is not linear — it accelerates dramatically (33 GB → 60 GB in 6 minutes)
• CPU idle drops to 0.0% as the system thrashes
• Load average exceeds 1,000 due to processes blocked on I/O
• The system freeze is a hard hang — no OOM killer logs, no kernel panic, journal shows corruption from unclean shutdown
• This happened every day across Feb 11–15 with consistent patterns
• Previous instance type was r7i.xlarge (4 vCPU, 32 GB) — upgraded to r7i.2xlarge (8 vCPU, 64 GB) thinking it was CPU, but the language server just consumed the additional memory

What was ruled out:

• CPU saturation — occurred with 50% CPU idle; the CPU spike is a consequence of OOM, not the cause
• sshd configuration — hardened keepalive settings, MaxSessions, MaxStartups; sshd itself is fine
• pam_systemd — disabled to prevent logind timeout; didn't fix the root cause
• Network/ENA driver — no errors in dmesg; network adapter is healthy
• Other processes — only language_server_linux_x64 shows unbounded growth

Workaround

A watchdog service that monitors the language server's RSS every 10 seconds and kill -9s it when it exceeds 16 GB. Windsurf auto-restarts the language server, resetting the leak. This prevents the system freeze but causes periodic brief reconnections.

Expected Behavior

language_server_linux_x64 should have stable memory usage and not grow unboundedly over time.

Suggested Investigation Areas

1. The Go binary may have a goroutine leak or unbounded cache/buffer growth
2. Possibly related to gRPC streaming state accumulation (see also issue # Windsurf IDE Freeze Bug Report #284 which reports 70+ duplicate gRPC calls)
3. May be specific to or exacerbated by Remote SSH connections where network latency causes state accumulation