Codex IDE extension freezes Ubuntu by repeatedly spawning codex-linux-sandbox / bash probe processes

What version of the IDE extension are you using?

26.609.30741

What subscription do you have?

ChatGPT Pro

Which IDE are you using?

Cursor

What platform is your computer?

Ubuntu 22.04, Linux kernel 6.8.0-60-generic, x86_64

What issue are you seeing?

The OpenAI Codex IDE extension causes my Ubuntu machine / Cursor session to become unresponsive. This happens when using the Codex IDE extension locally on Ubuntu, and I have also observed similar behavior when connecting to the same Ubuntu machine remotely from macOS via Codex SSH.

Cursor itself works normally, and Cursor’s own built-in AI/Codex functionality does not cause this issue. The problem appears specific to the OpenAI Codex IDE extension / Codex local agent runtime.

During the freeze, the process list shows repeated or stuck Codex-related local execution processes, including:
codex app-server
codex-linux-sandbox
CODEX_SNAPSHOT
bash
sh
timeout
sleep
type rg
Many processes are stuck in wait states such as:
pipe_read
do_wait
do_poll
futex_wait_queue
I also saw repeated kernel log lines like:
kernel read not supported for file /home/path (pid: XXXXX comm: sh)
This appears to happen even when subagents are disabled. Subagents seem to make the issue worse, but they are not required to reproduce the freeze.

I have already checked the following:

• The machine has 128 GB RAM and 64 GB swap, so this does not look like a normal OOM issue.
• service_tier is already set to fast.
• I do not see clear NVIDIA Xid, NVMe timeout, OOM, or kernel soft-lockup messages corresponding to the freeze.
• Cursor itself remains stable without the OpenAI Codex IDE extension.
• The issue appears tied to the Codex extension’s local app-server / sandbox / shell probing path.

Representative process snapshot during the freeze:
codex app-server ...
codex-linux-sandbox --sandbox-policy-cwd /home/casbot/HLmotion ...
/bin/bash -c ...
timeout 55 bash -lc ...
sleep 1
type rg
The UI becomes unresponsive and sometimes the whole Ubuntu session becomes effectively unusable. I can sometimes switch TTY, but command input is delayed or unresponsive. I have had to use SysRq REISUB or forcefully kill Codex-related processes.

What steps can reproduce the bug?

1. On Ubuntu 22.04, open Cursor and open my local robotics workspace at /home/casbot/HLmotion.
2. Open the OpenAI Codex IDE extension panel.
3. Ask Codex to perform a normal small code-editing task.
4. Even with subagents disabled, Cursor/Ubuntu becomes unresponsive.
5. During the freeze, ps shows Codex-related processes such as codex app-server, codex-linux-sandbox, CODEX_SNAPSHOT, bash/sh, timeout, sleep, and type rg, with processes stuck in wait states such as pipe_read, do_wait, do_poll, and futex_wait_queue.

The same class of issue also occurs when using the Codex CLI directly on the same Ubuntu machine, not only through the IDE extension. Running codex locally on Ubuntu can also trigger the machine to become unresponsive. I also observed similar behavior when connecting to this Ubuntu host remotely from macOS via Codex SSH.

I do not have a smaller deterministic reproducer yet. In this workspace, normal use of Codex can trigger the issue. Cursor itself and Cursor’s built-in AI/Codex functionality are stable; the problem appears specific to the OpenAI Codex IDE extension / CLI local agent runtime.

What is the expected behavior?

_No response_

Additional information

_No response_