net: SIGSEGV: segmentation violation .. net.cgoLookupIPCNAME

[gopherbot]

by stormgbs:

My go program crashed with errors:

SIGSEGV: segmentation violation
PC=0x3841478ce2
signal arrived during cgo execution

runtime.cgocall(0x4016c0, 0x7f60b4257748)
        /usr/local/go/src/pkg/runtime/cgocall.c:149 +0x11b fp=0x7f60b4257738
runtime.cmalloc(0x15)
        /usr/local/go/src/pkg/runtime/cgocall.c:200 +0x47 fp=0x7f60b4257760
net._Cfunc_CString(0xc211d68860, 0x14, 0x7f60fd34bf40)
        net/_obj/_cgo_defun.c:31 +0x2a fp=0x7f60b4257780
net.cgoLookupIPCNAME(0xc211d68860, 0x14, 0x0, 0x0, 0x0, ...)
        /usr/local/go/src/pkg/net/cgo_unix.go:94 +0x124 fp=0x7f60b4257858
net.cgoLookupIP(0xc211d68860, 0x14, 0x0, 0x0, 0x0, ...)
        /usr/local/go/src/pkg/net/cgo_unix.go:148 +0x69 fp=0x7f60b42578b0
net.lookupIP(0xc211d68860, 0x14, 0x0, 0x0, 0x0, ...)
        /usr/local/go/src/pkg/net/lookup_unix.go:64 +0x63 fp=0x7f60b42578f8
net.func·022(0xc96680, 0xc210071000, 0xc211d68860, 0x14)
        /usr/local/go/src/pkg/net/lookup.go:41 +0x2d fp=0x7f60b4257948
net.(*singleflight).Do(0xc96680, 0xc211d68860, 0x14, 0x7f60b42579e0, 0x0, ...)
        /usr/local/go/src/pkg/net/singleflight.go:45 +0x1de fp=0x7f60b4257990
net.lookupIPMerge(0xc211d68860, 0x14, 0x0, 0x0, 0x0, ...)
        /usr/local/go/src/pkg/net/lookup.go:42 +0xc0 fp=0x7f60b4257a40
net.lookupIPDeadline(0xc211d68860, 0x14, 0x0, 0x0, 0x0, ...)
        /usr/local/go/src/pkg/net/lookup.go:57 +0xd0 fp=0x7f60b4257ac8
net.resolveInternetAddr(0x747960, 0x3, 0xc211d68860, 0x17, 0x0, ...)
        /usr/local/go/src/pkg/net/ipsock.go:285 +0x395 fp=0x7f60b4257b80
net.resolveAddr(0x73b9e0, 0x4, 0x747960, 0x3, 0xc211d68860, ...)
        /usr/local/go/src/pkg/net/dial.go:104 +0x32a fp=0x7f60b4257c18
net.(*Dialer).Dial(0x7f60b4257d78, 0x747960, 0x3, 0xc211d68860, 0x17, ...)
        /usr/local/go/src/pkg/net/dial.go:153 +0xa7 fp=0x7f60b4257d30
net.Dial(0x747960, 0x3, 0xc211d68860, 0x17, 0x5126be, ...)
        /usr/local/go/src/pkg/net/dial.go:138 +0x75 fp=0x7f60b4257db8
net/http.(*Transport).dial(0xc210059200, 0x747960, 0x3, 0xc211d68860, 0x17, ...)
        /usr/local/go/src/pkg/net/http/transport.go:401 +0xd4 fp=0x7f60b4257e00
net/http.(*Transport).dialConn(0xc210059200, 0xc212d82330, 0xc21339d380, 0x0, 0x0)
        /usr/local/go/src/pkg/net/http/transport.go:444 +0x6e fp=0x7f60b4257f50
net/http.func·014()
        /usr/local/go/src/pkg/net/http/transport.go:419 +0x3e fp=0x7f60b4257fa0
runtime.goexit()
        /usr/local/go/src/pkg/runtime/proc.c:1394 fp=0x7f60b4257fa8
created by net/http.(*Transport).getConn
        /usr/local/go/src/pkg/net/http/transport.go:421 +0x11a

In my program, I only used http.PostForm(), somebody said disable cgo may be worked.
but I have used cgo to replace bytes.Buffer.
So is there a good solution to avoid this crash?

some of my go code:
//Post start_time or end_time or Log
func PostCronData(apitype string, v *url.Values) (ret []byte, err error) {
        var api string
        switch apitype {
        case "log":
                api = fmt.Sprintf("http://%s%s", Config.domain, Config.postLogApi)
        case "time":
                api = fmt.Sprintf("http://%s%s", Config.domain, Config.updateTimeApi)
        default:
                return nil, errors.New(fmt.Sprintf("Can not find such api: %s", apitype))
        }
        // fmt.Println("Api:", api)
        DLogger.Debug("Api: %s", api)
        resp, err := http.PostForm(api, *v)
        if err != nil {
                return nil, err
        }
        defer resp.Body.Close()
        var buf []byte
        buf, err = ioutil.ReadAll(resp.Body)
        if err != nil {
                return nil, err
        }
        ret = buf
        return
}

thx u all !

[dvyukov]

Comment 1:

>but I have used cgo to replace bytes.Buffer.
How do you do it? Corrupted C heap would explain he crash.

[ianlancetaylor]

Comment 2:

Which version of go are you using?
Can you show us your cgo code?

Labels changed: added repo-main, release-go1.3maybe.

[rsc]

Comment 3:

Status changed to TimedOut.