gemini-cli - 💡(How to fix) Fix CLI Crash on Tool Completion (ioctl(2) failed, EBADF) [1 comments, 2 participants]

What happened?

CLI Version: 0.40.1 (via @latest) Runtime: Bun (invoked with bunx --bun) Operating System: Linux

Summary

The CLI crashes with Error: ioctl(2) failed, EBADF immediately after a shell tool finishes execution. This occurs because a React-style UI update triggers a resizePty() call on a Pseudo-Terminal (PTY) whose file descriptor has already been closed by the tool's termination.

Reproduction Steps

1. Launch the CLI using the Bun runtime:

   bunx --bun @google/gemini-cli@latest

2. Execute a command that terminates quickly or uses a pipe to force an early exit:

   ps aux | head -n 20

3. The CLI will crash with a red error block the moment the tool finishes and the TUI attempts to render the success state.

Backtrace

ERROR  ioctl(2) failed, EBADF

 -     at unknown
 -<anonymous> (/tmp/bunx-1000-@google/gemini-cli@latest/node_modules/@lydell/node-pty/unixTerminal.js:243:13)
 -resizePty (/tmp/bunx-1000-@google/gemini-cli@latest/node_modules/@google/gemini-cli/bundle/chunk-UN6XCVMJ.js:285678:30)
 -<anonymous> (/tmp/bunx-1000-@google/gemini-cli@latest/node_modules/@google/gemini-cli/bundle/interactiveCli-VO2T47FA.js:7102:31)
 -commitHookEffectListMount (/tmp/bunx-1000-@google/gemini-cli@latest/node_modules/@google/gemini-cli/bundle/chunk-VWLKCG5Q.js:5252:30)

Related Issues

• google-gemini/gemini-cli: Issue #10523, Issue #10617 (P1: Crash on PTY resize)
• oven-sh/bun: Issue #27285 (Compatibility with node-pty/ioctl on Linux)

Root Cause Analysis

The crash is a race condition between the PTY teardown and the UI layout engine:

1. The Race: A tool finishes -> PTY is destroyed -> UI update triggers -> resizePty() is called.
2. The Catch Failure: The native error thrown by the node-pty C++ binding when using ioctl on an invalid descriptor does not have a .code property (e.g., it is undefined, not "EBADF").
3. The Result: The CLI's internal error handling likely checks for err.code === 'ESRCH' but misses this error because it only contains a .message string ("ioctl(2) failed, EBADF"). The unhandled exception then crashes the entire process.

Suggested Fix

Update the resizePty wrapper in the CLI bundle to perform a string-based check on the error message when .code is missing:

try {
  this.pty.resize(cols, rows);
} catch (err) {
  // node-pty native errors often lack .code; check message for EBADF
  if (err.code === 'ESRCH' || err.message?.includes('EBADF')) {
    return; // Safe to ignore during teardown
  }
  throw err;
}

What did you expect to happen?

CLI does not crash

Client information

• CLI Version: 0.40.1
• Git Commit: 7a382e066
• Operating System: linux v24.3.0
• Sandbox Environment: no sandbox
• Model Version: auto-gemini-3
• Auth Type: oauth-personal
• Memory Usage: 377.4 MB
• Terminal Name: VTE(8203)
• Terminal Background: #1c1c1f
• Kitty Keyboard Protocol: Unsupported

Login information

No response

Anything else we need to know?

No response