Fix browser shared executor cleanup deadlock

[neubig]

• A human has tested these changes.

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Why

Fixes #3309. Browser executor finalizers could contend on the shared executor singleton lock even when the executor being cleaned up was not the shared singleton. On Windows, that could deadlock if cleanup happened while BrowserToolSet.create() held the non-reentrant shared lock during executor construction.

Summary

• Construct new browser shared executors outside _shared_executor_lock and only publish them under the lock.
• Avoid acquiring _shared_executor_lock during BrowserToolExecutor.close() unless the executor is currently the shared singleton.
• Add regression coverage for constructing outside the shared lock and non-shared cleanup skipping the shared lock.

Issue Number

Fixes #3309

How to Test

Ran targeted browser toolset tests:

uv run pytest tests/tools/browser_use/test_browser_toolset.py -q
# 14 passed, 5 warnings in 0.09s

Ran pre-commit on changed files:

uv run pre-commit run --files openhands-tools/openhands/tools/browser_use/definition.py openhands-tools/openhands/tools/browser_use/impl.py tests/tools/browser_use/test_browser_toolset.py
# Ruff format: Passed
# Ruff lint: Passed
# PEP8 style check (pycodestyle): Passed
# Type check with pyright: Passed
# Check import dependency rules: Passed
# Check Tool subclass registration: Passed

I did not reproduce the original 30-minute Windows CI timeout locally because it is timing-sensitive and platform-specific. The new regression tests exercise the lock-ordering conditions that made the deadlock possible before this fix.

Video/Screenshots

N/A — backend test/tooling change only.

Type

• Bug fix
• Feature
• Refactor
• Breaking change
• Docs / chore

Notes

This PR was created by an AI agent (OpenHands) on behalf of the user.

---

Agent Server images for this PR

• GHCR package: https://github.com/OpenHands/agent-sdk/pkgs/container/agent-server

Variants & Base Images

Variant	Architectures	Base Image	Docs / Tags
java	amd64, arm64	eclipse-temurin:17-jdk	Link
python	amd64, arm64	nikolaik/python-nodejs:python3.13-nodejs22-slim	Link
golang	amd64, arm64	golang:1.21-bookworm	Link

Pull (multi-arch manifest)

# Each variant is a multi-arch manifest supporting both amd64 and arm64
docker pull ghcr.io/openhands/agent-server:6cebeee-python

Run

docker run -it --rm \
  -p 8000:8000 \
  --name agent-server-6cebeee-python \
  ghcr.io/openhands/agent-server:6cebeee-python

All tags pushed for this build

ghcr.io/openhands/agent-server:6cebeee-golang-amd64
ghcr.io/openhands/agent-server:6cebeee74ecec51ec0380c9bb6daa778f0e0db16-golang-amd64
ghcr.io/openhands/agent-server:openhands-fix-browser-executor-deadlock-golang-amd64
ghcr.io/openhands/agent-server:6cebeee-golang_tag_1.21-bookworm-amd64
ghcr.io/openhands/agent-server:6cebeee-golang-arm64
ghcr.io/openhands/agent-server:6cebeee74ecec51ec0380c9bb6daa778f0e0db16-golang-arm64
ghcr.io/openhands/agent-server:openhands-fix-browser-executor-deadlock-golang-arm64
ghcr.io/openhands/agent-server:6cebeee-golang_tag_1.21-bookworm-arm64
ghcr.io/openhands/agent-server:6cebeee-java-amd64
ghcr.io/openhands/agent-server:6cebeee74ecec51ec0380c9bb6daa778f0e0db16-java-amd64
ghcr.io/openhands/agent-server:openhands-fix-browser-executor-deadlock-java-amd64
ghcr.io/openhands/agent-server:6cebeee-eclipse-temurin_tag_17-jdk-amd64
ghcr.io/openhands/agent-server:6cebeee-java-arm64
ghcr.io/openhands/agent-server:6cebeee74ecec51ec0380c9bb6daa778f0e0db16-java-arm64
ghcr.io/openhands/agent-server:openhands-fix-browser-executor-deadlock-java-arm64
ghcr.io/openhands/agent-server:6cebeee-eclipse-temurin_tag_17-jdk-arm64
ghcr.io/openhands/agent-server:6cebeee-python-amd64
ghcr.io/openhands/agent-server:6cebeee74ecec51ec0380c9bb6daa778f0e0db16-python-amd64
ghcr.io/openhands/agent-server:openhands-fix-browser-executor-deadlock-python-amd64
ghcr.io/openhands/agent-server:6cebeee-nikolaik_s_python-nodejs_tag_python3.13-nodejs22-slim-amd64
ghcr.io/openhands/agent-server:6cebeee-python-arm64
ghcr.io/openhands/agent-server:6cebeee74ecec51ec0380c9bb6daa778f0e0db16-python-arm64
ghcr.io/openhands/agent-server:openhands-fix-browser-executor-deadlock-python-arm64
ghcr.io/openhands/agent-server:6cebeee-nikolaik_s_python-nodejs_tag_python3.13-nodejs22-slim-arm64
ghcr.io/openhands/agent-server:6cebeee-golang
ghcr.io/openhands/agent-server:6cebeee74ecec51ec0380c9bb6daa778f0e0db16-golang
ghcr.io/openhands/agent-server:openhands-fix-browser-executor-deadlock-golang
ghcr.io/openhands/agent-server:6cebeee-golang_tag_1.21-bookworm
ghcr.io/openhands/agent-server:6cebeee-java
ghcr.io/openhands/agent-server:6cebeee74ecec51ec0380c9bb6daa778f0e0db16-java
ghcr.io/openhands/agent-server:openhands-fix-browser-executor-deadlock-java
ghcr.io/openhands/agent-server:6cebeee-eclipse-temurin_tag_17-jdk
ghcr.io/openhands/agent-server:6cebeee-python
ghcr.io/openhands/agent-server:6cebeee74ecec51ec0380c9bb6daa778f0e0db16-python
ghcr.io/openhands/agent-server:openhands-fix-browser-executor-deadlock-python
ghcr.io/openhands/agent-server:6cebeee-nikolaik_s_python-nodejs_tag_python3.13-nodejs22-slim

About Multi-Architecture Support

• Each variant tag (e.g., 6cebeee-python) is a multi-arch manifest supporting both amd64 and arm64
• Docker automatically pulls the correct architecture for your platform
• Individual architecture tags (e.g., 6cebeee-python-amd64) are also available if needed

[github-actions]

Python API breakage checks — ✅ PASSED

Result: ✅ PASSED

Action log

[github-actions]

REST API breakage checks (OpenAPI) — ✅ PASSED

Result: ✅ PASSED

Action log

[github-actions]

Coverage Report •

File	Stmts	Miss	Cover	Missing
openhands-tools/openhands/tools/browser_use
definition.py	197	73	62%	54–57, 72–74, 76–79, 82–84, 86–88, 90–92, 96, 99–100, 103–105, 116–117, 120–121, 124–125, 130–131, 133, 180, 230, 277, 321, 368, 412, 450, 488, 531, 573, 614, 662, 712, 758, 799–801, 815–818, 820–821, 823, 827–831, 833–836, 838, 841–842, 858–859
impl.py	321	201	37%	58–62, 64–65, 67, 69, 71–74, 76–77, 79, 81, 88, 108, 113, 119–125, 131, 137, 150–158, 165–167, 187–188, 192–193, 200–202, 214–217, 223–224, 229, 231–233, 235–236, 244–246, 248–252, 257, 296–302, 305–307, 309, 322, 359–360, 364, 375, 390–391, 396, 413, 419–420, 425, 430, 436–437, 441–442, 448–449, 457–460, 465–467, 474, 482, 500–501, 503–516, 519–532, 534–535, 541, 546–549, 557, 559, 562–563, 569–570, 575–576, 582–583, 587–588, 592–593, 597, 599–600, 602–605, 608–609, 615, 617, 619, 627–628, 632–633, 638–639, 643–644, 648–649, 654–655, 667–668, 679–680, 684–688, 702–704, 709, 714–715, 724–726
TOTAL	27204	13643	49%

[all-hands-bot]

🟡 Acceptable, but this PR currently has no effective diff: GitHub reports 0 changed files, and git diff 701a8dbc...6cebeee7 is empty. If the browser cleanup fix is already on main, this PR should likely be closed as a no-op; otherwise please rebase/reapply the intended changes so they are actually reviewable.

[RISK ASSESSMENT]

• [Overall PR] ⚠️ Risk Assessment: 🟢 LOW — merging the current head would not change code, but it also would not deliver the described fix.

VERDICT:
❌ Needs rework: the PR needs either a real diff or closure as already superseded.

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Workflow run: https://github.com/OpenHands/software-agent-sdk/actions/runs/26411135225

[neubig]

Closing this draft as a no-op: the PR now has 0 changed files against main, and the original fix changes are already present on the current branch/base. This was checked with gh pr diff 3310 --name-only returning no files.\n\n_This comment was created by an AI agent (OpenHands) on behalf of the user._