net/http: race in TestTransportAndServerSharedBodyRace

[mikioh]

See http://build.golang.org/log/9493424c051981be4ce433ab4997c99c79ebe783.

==================
WARNING: DATA RACE
Write by goroutine 100:
  net/http.(*body).Close()
      C:/workdir/go/src/net/http/transfer.go:788 +0x12e
  net/http.(*Request).closeBody()
      C:/workdir/go/src/net/http/request.go:1006 +0x7e
  net/http.(*persistConn).writeLoop()
      C:/workdir/go/src/net/http/transport.go:1022 +0x3bb

Previous read by goroutine 98:
  net/http.(*chunkWriter).writeHeader()
      C:/workdir/go/src/net/http/server.go:884 +0xfdc
  net/http.(*chunkWriter).Write()
      C:/workdir/go/src/net/http/server.go:261 +0xbf
  bufio.(*Writer).flush()
      C:/workdir/go/src/bufio/bufio.go:562 +0x1ae
  bufio.(*Writer).Flush()
      C:/workdir/go/src/bufio/bufio.go:551 +0x41
  net/http.(*response).finishRequest()
      C:/workdir/go/src/net/http/server.go:1151 +0xa7
  net/http.(*conn).serve()
      C:/workdir/go/src/net/http/server.go:1363 +0x11c2

Goroutine 100 (running) created at:
  net/http.(*Transport).dialConn()
      C:/workdir/go/src/net/http/transport.go:693 +0x119a
  net/http.(*Transport).getConn.func4()
      C:/workdir/go/src/net/http/transport.go:549 +0x7a

Goroutine 98 (running) created at:
  net/http.(*Server).Serve()
      C:/workdir/go/src/net/http/server.go:1908 +0x46b
==================
PASS
Found 1 data race(s)
FAIL    net/http    12.776s

[mikioh]

/CC @bradfitz

[bradfitz]

Looking. Mailed golang-dev before I saw this.

[bradfitz]

Sent https://go-review.googlesource.com/12909
/cc @jeddenlea

[gopherbot]

CL https://golang.org/cl/12909 mentions this issue.