[BUG] Immediate segmentation fault upon starting - claude (Bun runtime) segfaults at startup on Linux 6.17 / glibc 2.39 — all builds since Node→Bun switch

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?

I am NOT using the latest version because anything after 2.1.139 immediately segfaults.

Start any version 2.1.140 or above and immediate segmentation fault. Can't event run --version as it crashes out before getting as far as printing anything.

What Should Happen?

Claude code should start normally.

Error Messages/Logs

Starting any version after 2.1.139 (this is 2.2.146) immediately seg faults.

$ strace claude
brk(NULL) = 0x1f52b000
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7072abad8000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=93303, ...}) = 0
mmap(NULL, 93303, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7072abac1000
close(3) = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/librt.so.1", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0644, st_size=14624, ...}) = 0
mmap(NULL, 16400, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7072ababc000
mmap(0x7072ababd000, 4096, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1000) = 0x7072ababd000
mmap(0x7072ababe000, 4096, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x7072ababe000
mmap(0x7072ababf000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x7072ababf000
close(3) = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\220\243\2\0\0\0\0\0"..., 832) = 832
pread64(3, "\6\0\0\0\4\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0"..., 784, 64) = 784
fstat(3, {st_mode=S_IFREG|0755, st_size=2125328, ...}) = 0
pread64(3, "\6\0\0\0\4\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0"..., 784, 64) = 784
mmap(NULL, 2170256, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7072ab800000
mmap(0x7072ab828000, 1605632, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x28000) = 0x7072ab828000
mmap(0x7072ab9b0000, 323584, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1b0000) = 0x7072ab9b0000
mmap(0x7072ab9ff000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1fe000) = 0x7072ab9ff000
mmap(0x7072aba05000, 52624, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7072aba05000
close(3) = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libpthread.so.0", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0644, st_size=14408, ...}) = 0
mmap(NULL, 16400, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7072abab7000
mmap(0x7072abab8000, 4096, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1000) = 0x7072abab8000
mmap(0x7072abab9000, 4096, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x7072abab9000
mmap(0x7072ababa000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x7072ababa000
close(3) = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libdl.so.2", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0644, st_size=14408, ...}) = 0
mmap(NULL, 16400, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7072abab2000
mmap(0x7072abab3000, 4096, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1000) = 0x7072abab3000
mmap(0x7072abab4000, 4096, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x7072abab4000
mmap(0x7072abab5000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x7072abab5000
close(3) = 0
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libm.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0644, st_size=952616, ...}) = 0
mmap(NULL, 950296, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7072ab717000
mmap(0x7072ab727000, 520192, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x10000) = 0x7072ab727000
mmap(0x7072ab7a6000, 360448, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x8f000) = 0x7072ab7a6000
mmap(0x7072ab7fe000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xe7000) = 0x7072ab7fe000
close(3) = 0
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7072abab0000
mmap(NULL, 73728, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7072aba9e000
arch_prctl(ARCH_SET_FS, 0x7072abaae580) = 0
set_tid_address(0x7072abaae850) = 31937
set_robust_list(0x7072abaae860, 24) = 0
rseq(0x7072abaaeea0, 0x20, 0, 0x53053053) = 0
mprotect(0x7072ab9ff000, 16384, PROT_READ) = 0
mprotect(0x7072ab7fe000, 4096, PROT_READ) = 0
mprotect(0x7072abab5000, 4096, PROT_READ) = 0
mprotect(0x7072ababa000, 4096, PROT_READ) = 0
mprotect(0x7072ababf000, 4096, PROT_READ) = 0
mprotect(0x7072abb18000, 8192, PROT_READ) = 0
prlimit64(0, RLIMIT_STACK, NULL, {rlim_cur=8192*1024, rlim_max=RLIM64_INFINITY}) = 0
munmap(0x7072abac1000, 93303) = 0
--- SIGSEGV {si_signo=SIGSEGV, si_code=SI_KERNEL, si_addr=NULL} ---
+++ killed by SIGSEGV (core dumped) +++

Steps to Reproduce

Install claude code 2.1.146
Execute "claude"
Segmentation fault

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.139

Claude Code Version

2.1.146

Platform

AWS Bedrock

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Xterm

Additional Information

$ /home/johnsargent/.local/share/claude/versions/2.1.146 
Segmentation fault (core dumped)

✗ 139 ~ $ cat .claude/settings.json 
{
  "autoUpdaterStatus": "disabled",
  "env": {
    "DISABLE_AUTOUPDATER": "1",
    "DISABLE_AUTOUPDATES": "1",
    "CLAUDE_CODE_USE_BEDROCK": "1",
    "ANTHROPIC_MODEL": "opus",
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "global.anthropic.claude-opus-4-7",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "global.anthropic.claude-sonnet-4-5-20250929-v1:0",
    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "global.anthropic.claude-haiku-4-5-20251001-v1:0",
    "DISABLE_PROMPT_CACHING": "0"
  }
}

Tried removing the .claude directory so I get clean settings etc. - no difference, still segfault.

Tried with every version after 2.1.139 as it appeared but they all crash out in the same way, so I assume something was introduced in 2.1.140 that caused the issue and that persists

Would attach the core file, but it obviously contains API keys and the like, so I can't.

This is on Ubuntu 24.04 - this is NOT a duplicate of all the Windows segmentation fault issues for different versions or after running certain operations. This doesn't even get as far as fully loading.