[BUG] Segfault on startup persists in 2.1.246 (Bun runtime, SIGSEGV at si_addr=NULL) — regression of #62747

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?

Same failure mode as #62747, recurring in a much newer build.

Claude Code version (broken): 2.1.246
Last known working version: 2.1.235
OS: Arch Linux
Kernel: 7.1.9-arch1-2
glibc: 2.44
Arch: x86_64

claude --version segfaults immediately, before any output.

dmesg:
claude[903906]: segfault at 0 ip 0000000001d10458 sp 00007ffe7cffc960 error 4 in claude.exe[1b0f458,1953000+3b33000] likely on CPU 5 (core 5, socket 0)
strace tail:
--- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=NULL} ---
+++ killed by SIGSEGV (core dumped) +++

Ruled out: /tmp noexec, ASLR, vm.overcommit_memory, ulimits, environment variables, transparent hugepages (tried madvise). Binary itself is a valid, non-truncated x86_64 ELF (verified with file). Installing 2.1.235 instead resolves it completely — claude --version and normal startup both work.

Given kernel 7.1.9 is very recent, this looks like the same Bun-runtime/kernel-compatibility class of bug as #62747, #76241, and #27699, possibly reintroduced or never fully fixed for newer kernels.

What Should Happen?

claude --version and claude should start normally without crashing, as they did in version 2.1.235.

Error Messages/Logs

dmesg output:
claude[903906]: segfault at 0 ip 0000000001d10458 sp 00007ffe7cffc960 error 4 in claude.exe[1b0f458,1953000+3b33000] likely on CPU 5 (core 5, socket 0)

strace tail:
--- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=NULL} ---
+++ killed by SIGSEGV (core dumped) +++

Steps to Reproduce

1. Install @anthropic-ai/claude-code@2.1.246 (npm install -g @anthropic-ai/claude-code@2.1.246)
2. Run claude --version
3. Process immediately crashes with segmentation fault, no output printed

Downgrading to 2.1.235 (npm install -g @anthropic-ai/claude-code@2.1.235) resolves the issue completely — claude --version and claude both start normally.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.235

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

_No response_