net: TestSplice hangs on old versions of linux

[benburkert]

Please answer these questions before submitting your issue. Thanks!

What did you do?

go test -run TestSplice net

What did you expect to see?

The tests to run successfully.

What did you see instead?

The tests hang.

System details

go version go1.10.2 linux/386
GOARCH="386"
GOBIN=""
GOCACHE="/root/.cache/go-build"
GOEXE=""
GOHOSTARCH="386"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/root/go"
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_386"
GCCGO="gccgo"
GO386="sse2"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m32 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build202917466=/tmp/go-build -gno-record-gcc-switches"
GOROOT/bin/go version: go version go1.10.2 linux/386
GOROOT/bin/go tool compile -V: compile version go1.10.2
uname -sr: Linux 2.6.24-16-server
Distributor ID:	Ubuntu
Description:	Ubuntu 8.04
Release:	8.04
Codename:	hardy

[benburkert]

The splice syscall is buggy on older versions of linux. Instead of returning 0 when reading from a closed TCP socket, it returns-EAGAIN. This causes poll.Splice() to loop forever because the EAGAIN is interpreted as the socket being not ready to read.

[gopherbot]

Change https://golang.org/cl/113999 mentions this issue: internal/poll: disable splice on old linux versions