plugin: plugin.Open() segfault with statically linked binaries

[d1vyank]

What version of Go are you using (go version)?
go version go1.9 linux/amd64

Does this issue reproduce with the latest release?
Yes

What operating system and processor architecture are you using (go env)?
GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/opt/gopath"
GORACE=""
GOROOT="/opt/go"
GOTOOLDIR="/opt/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build683959130=/tmp/go-build -gno-record-gcc-switches"
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"

What did you do?
Compiled the simple plugin example described in the plugin docs with the -static flag
go run -ldflags '-extldflags "-static"' main.go

What did you expect to see?
The same output as building without the -static flag:
go run main.go
Hello, number 7

What did you see instead?
Segfault in cgo runtime:

go run -ldflags '-extldflags "-static"' main.go
# command-line-arguments
/tmp/go-link-658275617/000000.o: In function `pluginOpen':
/tmp/workdir/go/src/plugin/plugin_dlopen.go:19: warning: Using 'dlopen' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
fatal error: unexpected signal during runtime execution
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x0]

runtime stack:
runtime.throw(0x52c324, 0x2a)
/opt/go/src/runtime/panic.go:605 +0x95
runtime.sigpanic()
/opt/go/src/runtime/signal_unix.go:351 +0x2b8

goroutine 1 [syscall, locked to thread]:
runtime.cgocall(0x459260, 0xc420053c18, 0xc42000e010)
/opt/go/src/runtime/cgocall.go:132 +0xe4 fp=0xc420053be8 sp=0xc420053ba8 pc=0x401f84
plugin._Cfunc_pluginOpen(0x25cdfe0, 0xc42000e010, 0x0)
plugin/_obj/_cgo_gotypes.go:98 +0x4e fp=0xc420053c18 sp=0xc420053be8 pc=0x45758e
plugin.open.func3(0x25cdfe0, 0xc42000e010, 0xc42001c0a0)
/tmp/workdir/go/src/plugin/plugin_dlopen.go:102 +0xae fp=0xc420053c58 sp=0xc420053c18 pc=0x4589ae
plugin.open(0x52ce1a, 0x4c, 0x0, 0x0, 0x0)
/tmp/workdir/go/src/plugin/plugin_dlopen.go:102 +0x1d1 fp=0xc420053e88 sp=0xc420053c58 pc=0x457c31
plugin.Open(0x52ce1a, 0x4c, 0xc42007a000, 0xe, 0xc420012000)
/opt/go/src/plugin/plugin.go:31 +0x35 fp=0xc420053ec0 sp=0xc420053e88 pc=0x4570c5
main.loadPlugins()

[ianlancetaylor]

I would not count on this ever working. If someone wants to figure out how to fix it, great, but otherwise it seems both difficult and low priority.

[ianlancetaylor]

CC @crawshaw

[crawshaw]

As Ian says, difficult and low priority. Unless an intrepid sort with the need and tenacity shows up to implement this, it won't happen.

I suppose we could produce a link-time error easily enough if both the -static flag and the plugin.Open symbol are present. The current run time error seems quite clear though.

[wgerlach]

It would be nice if the documentation https://golang.org/pkg/plugin/ were more clear about the limitations. Also see issues raised in this thread: https://www.reddit.com/r/golang/comments/b6h8qq/is_anyone_actually_using_go_plugins/ejkxd2k/