[Ajay R (AjayMsft9)]

Description

Fix reboot detection when the who -b boot-time lookup reaches its function timeout.

FunctionTimedOut derives from BaseException, so it bypassed the existing except Exception handler and prevented the uptime fallback from running. This change handles the timeout explicitly, falls back to uptime -s, logs the fallback reason, and adds regression coverage.

Related Issue

Type of Change

• Bug fix
• New feature
• Breaking change
• Refactoring
• Documentation update

Checklist

• Description is filled in above
• No credentials, secrets, or internal details are included
• Peer review requested (if not, add required peer reviewers after raising PR)
• Tests executed and results posted below

Test Validation

Key Test Cases:
smoke_test|verify_cpu_count

Impacted LISA Features:
None (shared Reboot tool behavior)

Tested Azure Marketplace Images:

• Not applicable (bare-metal validation used Ubuntu 22.04 Jammy)

Test Results

Image	VM Size	Result
Ubuntu 22.04 Jammy	N/A (bare-metal)	PASSED

Additional checks: Reboot self-tests, Black, Flake8, Pylint, and Mypy passed.

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