fix: handle stale runner processes with deleted binaries

[sbryngelson]

Summary

• find_pids now strips the (deleted) suffix that Linux appends to /proc/PID/exe when a runner binary is replaced on disk
• Without this, runners with stale binaries are invisible to find_node and restart-all, appearing offline even though the process is alive
• Fixes the case where restart-all reports runners as OFFLINE and skips them instead of restarting them

Test plan

• Verify restart-all detects and restarts runners whose binaries have been updated on disk
• Verify find_node correctly locates runners with deleted binaries
• Verify stop_runner correctly kills stale processes before starting fresh ones

🤖 Generated with Claude Code

[github-actions]

Claude Code Review

Head SHA: 2d0335aa5d66bf1b5fdb1f995c2fd642fdbf2371

Files changed: 1

• misc/runners/common/runner-lib.sh

Summary:

• Adds exe=${exe% (deleted)} to find_pids() to strip the Linux kernel suffix appended to /proc/PID/exe when the underlying binary inode is replaced on disk
• Fixes runner detection failure after binary updates (runner appears OFFLINE to find_node/restart-all despite being alive)
• Change is minimal, correct, and safe (pure shell parameter expansion, no injection risk)

Findings:

No blocking issues. The analogous sweep_all_nodes function is unaffected: it derives dir via two dirname calls on the exe path, which strip the filename (and any trailing (deleted) suffix) before the value is used or printed. No fix is needed there.

[Copilot]

Pull request overview

This PR improves GitHub Actions runner process discovery on login nodes by handling the Linux /proc/<pid>/exe symlink behavior when the underlying runner binary has been deleted.

Changes:

• Strip the trailing (deleted) suffix from resolved executable paths in find_pids() before comparing against the expected Runner.Listener path.

[github-actions]

Claude Code Review

Head SHA: 2d0335a

Files changed:

• 1
• misc/runners/common/runner-lib.sh

Findings:

sweep_all_nodes() has the same (deleted) problem but was not fixed

The fix strips (deleted) from exe in find_pids(), but sweep_all_nodes() (in the same file, visible in context) has an identical /proc/$p/exe resolution pattern with no corresponding fix:

exe=$(readlink -f /proc/$p/exe 2>/dev/null || true)
[ -z "$exe" ] && continue
dir=$(dirname "$(dirname "$exe")")

If the runner binary has been updated while the process is running, readlink -f /proc/$p/exe returns something like /path/to/bin/Runner.Listener (deleted). The [ -z "$exe" ] guard does not catch this — exe is non-empty — so dir is computed via dirname dirname of a path ending in (deleted). The resulting dir would be wrong (e.g. the (deleted) suffix being treated as part of the innermost path component), causing sweep_all_nodes() to report the wrong runner directory and emit a malformed RUNNER output line.

The same one-line fix should be applied to sweep_all_nodes() immediately after its readlink call:

exe=${exe% (deleted)}

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: b729d8d6-729c-4e07-84ad-c8252a855b44

📥 Commits

Reviewing files that changed from the base of the PR and between 5c74f9f and 2d0335a.

📒 Files selected for processing (1)

• misc/runners/common/runner-lib.sh

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📝 Walkthrough

Walkthrough

The find_pids function in the runner library script was updated to handle executable path comparison more accurately. After resolving the executable path of a running process, the code now removes any trailing " (deleted)" suffix from the path before comparing it against the target Runner.Listener path. This adjustment accounts for scenarios where the original binary has been deleted but the process still maintains a reference to it through the executable symlink. The modification adds a single line and does not alter other logic or error handling mechanisms.

📝 Coding Plan

• Generate coding plan for human review comments

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