x/net/http2: data race in TestCanonicalHeaderCacheGrowth

[bcmills]

#!watchflakes
post <- pkg == "x/net/http2" && test == "TestCanonicalHeaderCacheGrowth" && `DATA RACE`

https://build.golang.org/log/9f76836a9c3da1bd2d60e0e4b5274e6d253febaa:

==================
WARNING: DATA RACE
Write at 0x000001a1e0cc by goroutine 67:
  golang.org/x/net/http2.disableGoroutineTracking()
      C:/workdir/gopath/src/golang.org/x/net/http2/server_test.go:3502 +0x64
  golang.org/x/net/http2.TestCanonicalHeaderCacheGrowth()
      C:/workdir/gopath/src/golang.org/x/net/http2/server_test.go:4550 +0x9b
  testing.tRunner()
      C:/workdir/go/src/testing/testing.go:1439 +0x213
  testing.(*T).Run.func1()
      C:/workdir/go/src/testing/testing.go:1486 +0x47

Previous read at 0x000001a1e0cc by goroutine 248:
  golang.org/x/net/http2.goroutineLock.checkNotOn()
      C:/workdir/gopath/src/golang.org/x/net/http2/gotrack.go:41 +0xaa
  golang.org/x/net/http2.(*serverConn).writeFrameFromHandler()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:1134 +0x75
  golang.org/x/net/http2.(*serverConn).writeHeaders()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:2331 +0x116
  golang.org/x/net/http2.(*responseWriterState).writeChunk()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:2617 +0x10f2
  golang.org/x/net/http2.chunkWriter.Write()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:2520 +0xb5
  golang.org/x/net/http2.(*responseWriter).FlushError()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:2790 +0xbb
  golang.org/x/net/http2.(*responseWriter).Flush()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:2774 +0x78
  golang.org/x/net/http2.(*responseWriter).handlerDone()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:2952 +0x6e
  golang.org/x/net/http2.(*serverConn).runHandler.func1()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:2303 +0x3de
  runtime.deferreturn()
      C:/workdir/go/src/runtime/panic.go:436 +0x32
  golang.org/x/net/http2.(*serverConn).processHeaders.func1()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:2018 +0x64

Goroutine 67 (running) created at:
  testing.(*T).Run()
      C:/workdir/go/src/testing/testing.go:1486 +0x724
  testing.runTests.func1()
      C:/workdir/go/src/testing/testing.go:1839 +0x99
  testing.tRunner()
      C:/workdir/go/src/testing/testing.go:1439 +0x213
  testing.runTests()
      C:/workdir/go/src/testing/testing.go:1837 +0x7e4
  testing.(*M).Run()
      C:/workdir/go/src/testing/testing.go:1719 +0xa71
  main.main()
      _testmain.go:767 +0x2e4

Goroutine 248 (finished) created at:
  golang.org/x/net/http2.(*serverConn).processHeaders()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:2018 +0xd39
  golang.org/x/net/http2.(*serverConn).processFrame()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:1518 +0x635
  golang.org/x/net/http2.(*serverConn).processFrameFromReader()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:1461 +0x2ed
  golang.org/x/net/http2.(*serverConn).serve()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:952 +0x15ea
  golang.org/x/net/http2.(*Server).ServeConn()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:531 +0x1771
  golang.org/x/net/http2.ConfigureServer.func1()
      C:/workdir/gopath/src/golang.org/x/net/http2/server.go:321 +0x124
  net/http.(*conn).serve()
      C:/workdir/go/src/net/http/server.go:1874 +0x1c56
  net/http.(*Server).Serve.func3()
      C:/workdir/go/src/net/http/server.go:3071 +0x58
==================
--- FAIL: TestCanonicalHeaderCacheGrowth (86.60s)
    testing.go:1312: race detected during execution of test
FAIL
FAIL	golang.org/x/net/http2	111.467s

[bcmills]

This is the regression test added for #56350 in CL 455635 (attn @neild).

[dmitshur]

Damien investigated this problem in the backports, and found the fix was to set serveG (see here). The same fix just needs to be applied to the main branch too.

[gopherbot]

Change https://go.dev/cl/456523 mentions this issue: http2: fix race in TestCanonicalHeaderCacheGrowth