[BUG] claude install hangs indefinitely at 99% CPU with no network activity (2.1.289, Linux x64)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Summary

The native installer's install step spins at ~100% CPU indefinitely. After 1 hour the process had accumulated 1:04:26 of CPU time and never completed. The process holds no network sockets, so it is not stalled on a download — it appears stuck in a local busy loop.

Environment
Claude Code version: 2.1.289 (native installer, linux-x64)
Install method: curl -fsSL https://claude.ai/install.sh | bash
OS: Ubuntu 22.04
Kernel: Linux 5.15.0-185-generic #195-Ubuntu SMP Fri Jun 19 17:11:50 UTC 2026 x86_64
Arch: x64
RAM: 4 GB (meets the documented 4 GB+ requirement)
Steps to reproduce
Run curl -fsSL https://claude.ai/install.sh | bash on Ubuntu 22.04 x64
The download completes and the installer proceeds to its install step
The process never exits

What Should Happen?

Installation completes within a reasonable time (normally well under a minute) and claude --version works.

Error Messages/Logs

Steps to Reproduce

Actual behavior

The process runs indefinitely at ~99% CPU. Still running after 1 hour:

$ ps -ef | grep claude
syncs 1047528 1047466 99 10:30 pts/1 01:04:26 /home/syncs/.claude/downloads/claude-2.1.289-linux-x64 install

Note that elapsed wall time (~1h) and accumulated CPU time (1:04:26) are nearly identical — the process is saturating a core continuously, not waiting on anything.

Diagnostics

Process state — running on CPU, not blocked on I/O:

$ cat /proc/1047528/status | grep -iE "^State|^Threads|VmRSS"
State:    R (running)
VmRSS:    106776 kB
Threads:  4

$ cat /proc/1047528/wchan
0

State: R with an empty wchan confirms the process is actively executing, not sleeping in a kernel call.

Open file descriptors — no sockets at all:

$ ls -l /proc/1047528/fd
lr-x------ 1 syncs syncs 64 Oct  5 11:20 0 -> pipe:[47555979]
lrwx------ 1 syncs syncs 64 Oct  5 11:20 1 -> /dev/pts/1
lrwx------ 1 syncs syncs 64 Oct  5 11:20 2 -> /dev/pts/1
lrwx------ 1 syncs syncs 64 Oct  5 11:20 3 -> anon_inode:[eventpoll]
lrwx------ 1 syncs syncs 64 Oct  5 11:20 4 -> anon_inode:[eventfd]
lr-x------ 1 syncs syncs 64 Oct  5 11:20 5 -> /dev/urandom
lr-x------ 1 syncs syncs 64 Oct  5 11:20 6 -> /proc/1047528/statm
lrwx------ 1 syncs syncs 64 Oct  5 10:30 7 -> /dev/pts/1

There is no socket fd, which rules out a slow or stalled network transfer. fd 6 is an open handle to the process's own /proc/<pid>/statm — possibly a self-monitoring poll loop that never reaches an exit condition.

Resources are not the constraint:

$ free -m
               total   used   free   shared  buff/cache   available
Mem:            3911    824    426       17        2660        2778
Swap:           2047    215       1832

$ df -h ~
Filesystem                         Size  Used Avail Use% Mounted on
/dev/mapper/ubuntu--vg-ubuntu--lv   29G   24G  3.8G  87% /

2.7 GB available memory, minimal swap usage, 3.8 GB free disk. Not an OOM, thrashing, or disk-full condition.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

not yeah install

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_