Crash in Iconv.DoWrite

[RinTohsaka]

Hello! I'm not sure if it's issue with iconv or Go iteself, but my program randomly crashes. The code:

func main() {
        in := make(chan []byte)
        dir := os.Args[1]
        files, err := ioutil.ReadDir(dir)
        if err != nil {
                panic(err)
        }

        go func() {
                cd, err := iconv.Open("UTF-8", "CP932")
                if err != nil {
                        panic(err)
                }
                for data := range in {
                        cd.ConvString(string(data))
                }
        }()

        iterations := 1000
        for i := 0; i < iterations; i++ {
                for _, file := range files {
                        file, err := os.Open(path.Join(dir, file.Name()))
                        if err != nil {
                                panic(err)
                        }
                        data, err := ioutil.ReadAll(file)
                        if err != nil {
                                panic(err)
                        }
                        in <- data
                        file.Close()
                }
        }
        close(in)
}

And after some (random) time executing this code program crashes with:

runtime:objectstart Span weird: p=0xc820880000 k=0x6410440 s.start=0xc820880000 s.limit=0xc820884000 s.state=2
fatal error: objectstart: bad pointer in unexpected span

exit status 2
1: running [Created by runtime.gcBgMarkStartWorkers @ mgc.go:1239]
    runtime panic.go:527                throw(0x542a00, 0x2b)
    runtime mbitmap.go:217              heapBitsForObject(0xc820880000, 0, 0, 0xc800000000, 0x7fa7d82f41a0)
    runtime mgcmark.go:878              scanobject(0xc820770208, #1)
    runtime mgcmark.go:689              gcDrain(#1, 0x7d0)
    runtime mgc.go:1320                 gcBgMarkWorker(0xc820028000)
    runtime asm_amd64.s:1696            goexit()
1: runnable [locked] [Created by main.main @ test.go:44]
    iconv   _cgo_gotypes.go:49          _C2func_iconv(#14, #4, #9, #12, #11, 0xffffffffffffffff, 0, 0)
    iconv   iconv.go:102                Iconv.DoWrite(#14, #15, #10, #8, 0x1a38, 0x1e04, 0x1a38, #5, 0x200, 0x200, ...)
    iconv   iconv.go:61                 Iconv.Conv(#14, #7, 0x1c34, 0x2000, #5, 0x200, 0x200, 0, 0, 0, ...)
    iconv   iconv.go:68                 Iconv.ConvString(#14, #6, 0x1c34, 0, 0)
    main    test.go:42                  main.func1(#2)
1: runnable
    syscall asm_linux_amd64.s:18        Syscall(0x3, 0x3, 0, 0, 0, 0, 0)
    syscall zsyscall_linux_amd64.go:296 Close(0x3, 0, 0)
    os      file_unix.go:126            (*file).close(#3, 0, 0)
    os      file_unix.go:118            (*File).Close(#13, 0, 0)
    main    test.go:58                  main()
1: syscall [locked]
    runtime asm_amd64.s:1696            goexit()

I'm using Go 1.5.2 installed with gvm under Ubuntu Linux 14.04.3 LTS (x86_64). After some googling i found this issue, but it supposedly fixed in 1.5.2.
Any advice?

[xushiwei]

@RinTohsaka Does it crash in Go 1.6.x?