tailscale/tailscale

magicsock_unix_test fails when the machine already has higher buffer sizes

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#15,994 建立於 2025年5月16日

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描述

What is the issue?

https://github.com/tailscale/tailscale/blob/9c52856af62074e51f125a90b4153fab61a13b00/wgengine/magicsock/magicsock_unix_test.go#L43-L47

The test applies the buffer size setting, and then checks that the buffer size goes up. If building Tailscale on a machine where the buffer size is already set higher than the Tailscale defaults, the buffer size doesn't go up - it goes down. The test then, obviously, fails.

Steps to reproduce

sysctl -w net.core.wmem_default=16777216, then build Tailscale

Are there any recent changes that introduced the issue?

No response

OS

Linux

OS version

NixOS unstable

Tailscale version

1.82.5

Other software

No response

Bug report

No response

貢獻者指南

技術棧
gorest api
領域
testingbackend
議題類型
bug
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
2
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
1-3 hours
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
fresh
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
Gounderstanding of test assertions
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
80
研究方向
The test at wgengine/magicsock/magicsock unix test.go lines 43-47 checks that after setting a buffer size, the buffer size increases. However, on systems where the current buffer size is already higher than the target, setting the value actually decreases it, causing the test to fail. The fix should make the test robust by either measuring the initial value and asserting the final value is within a range, or by checking that the buffer size is set to the requested value regardless of direction. The test file already exists and uses syscall.SetsockoptInt; a diff can be reviewed against the linked source.
magicsock_unix_test fails when the machine already has higher buffer sizes · tailscale/tailscale#15994 | Good First Issue