reflect : crash after syscall.FreeLibrary()

[SolarTDX]

Please answer these questions before submitting your issue. Thanks!

What version of Go are you using (go version)?

go version go1.10 windows/amd64

gcc 7.3.0

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

windows 7

set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\Administrator\AppData\Local\go-build
set GOEXE=.exe
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOOS=windows
set GOPATH=D:\go\
set GORACE=
set GOROOT=C:\Go
set GOTMPDIR=
set GOTOOLDIR=C:\Go\pkg\tool\windows_amd64
set GCCGO=gccgo
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -fmessage-length=0 -fdebug-prefix-map=C:\Users\ADMINI~1\AppData\Local\Temp\go-build018223022=/tmp/go-build -gno-record-gcc-switches

What did you do?

demo.go

package main

import "C"

import (
	"fmt"
	"syscall"
)

//export one
func one(in uintptr) uintptr {
	return in
}

func main() {
	fmt.Println("Please enter some input: ")
l_for:
	for {
		in := ""
		if _, err := fmt.Scanln(&in); err != nil {
			break
		}
		switch in {
		case "wait":
			continue
		case "exit":
			break l_for
		default:
			callOne()
		}
	}
	fmt.Println("success!")
}

func callOne() {
	fmt.Println("in call!")
	var err error
	var h syscall.Handle
	if h, err = syscall.LoadLibrary("one"); err != nil {
		return
	}
	defer syscall.FreeLibrary(h)
	var fn uintptr
	if fn, err = syscall.GetProcAddress(h, "one"); err != nil {
		return
	}
	a, b, c := syscall.Syscall(fn, 1, 0, 0, 0)
	fmt.Println(a, b, c)
	fmt.Println("out call!")
}

I run

D:\go\src\tdx\demo>go build demo.go

D:\go\src\tdx\demo>go build -o one.dll -buildmode=c-shared demo.go

D:\go\src\tdx\demo>demo
Please enter some input:
call
in call!
0 0 The operation completed successfully.
out call!

D:\go\src\tdx\demo>

What did you expect to see?

"success!" in the end of demo

What did you see instead?

crash

[odeke-em]

/cc @alexbrainman @ianlancetaylor

[alexbrainman]

I think this is a duplicate of #22192

No?

Alex

[SolarTDX]

@alexbrainman

#22192 This issue can't solve my questions

I think they are different situations

My another project is VS2010 -- exe, Go1.10 -- dll, also crash after "syscall.FreeLibrary()"

In Windbg , I see some threads are running on <Unloaded_one.DLL>, maybe Go-threads of one.dll did not exit after "syscall.FreeLibrary()"

[AlexRouSg]

@alexbrainman
I believe this is #11100 which states that c-shared and plugins once loaded cannot be freed/closed

[alexbrainman]

#22192 This issue can't solve my questions

I think they are different situations

@SolarTDX issue #22192 is about Go program loading Go DLL. That is what your program above does. Doesn't it? So you get the crash just like user of #22192. That is not supported at this moment.

I believe this is #11100 which states that c-shared and plugins once loaded cannot be freed/closed

@AlexRouSg it is possible. I did not investigate properly. #22192 is bad enough to make program crash immediately. What happens after is not relevant.

Closing this is a duplicate of #22192 and #11100. Please comment if disagree,

Alex