diff --git a/log.go b/log.go
index 48e7a8e..9954119 100644
--- a/log.go
+++ b/log.go
@@ -61,6 +61,7 @@ type Logger struct {
 	module    string
 	golog     *log.Logger
 	loglevel  LogLevel
+	skipfunc  func(string) bool
 	calldepth int
 }
 
@@ -108,6 +109,11 @@ func (log *Logger) SetCalldepth(calldepth int) {
 	log.calldepth = calldepth
 }
 
+// SetSkipfunc set skip func to skip stack filename
+func (log *Logger) SetSkipfunc(skipfunc func(string) bool) {
+	log.skipfunc = skipfunc
+}
+
 func (log *Logger) Print(prefix string, v interface{}) {
 	var str = ""
 	if pkg, err := json.Marshal(v); err != nil {
@@ -198,7 +204,7 @@ func (log *Logger) logwrite(typ LogLevel, calldepth int, format string, v ...int
 	calldepth += log.calldepth
 	var (
 		idstr  = log.GetLogidStr(" [%s]")
-		header = formatHeader(calldepth) + "$" + idstr
+		header = formatHeader(calldepth, log.skipfunc) + "$" + idstr
 	)
 
 	format = strings.Trim(format, "\n")
@@ -238,7 +244,7 @@ func (log *Logger) logwrite(typ LogLevel, calldepth int, format string, v ...int
 	}
 }
 
-func formatHeader(calldepth int) string {
+func formatHeader(calldepth int, skipfunc func(string) bool) string {
 	const MAX_LENGTH = 35 /* + 22 */
 	// log time
 	now := time.Now()
@@ -248,10 +254,17 @@ func formatHeader(calldepth int) string {
 		year, month, day, hour, min, sec, now.Nanosecond()/1e6)
 
 	// log position
-	_, file, line, ok := runtime.Caller(calldepth)
-	if !ok {
-		file = "???"
-		line = 0
+	pcs := [13]uintptr{}
+	cnt := runtime.Callers(calldepth+1, pcs[:])
+	frames := runtime.CallersFrames(pcs[:cnt])
+	file, line := "???", 0
+	for i := 0; i < cnt; i++ {
+		frame, more := frames.Next()
+		fmt.Println(i, "\t", frame.File, frame.Line)
+		if !more || skipfunc == nil || !skipfunc(frame.File) {
+			file, line = frame.File, frame.Line
+			break
+		}
 	}
 
 	// Case 1: too short path, return directly
diff --git a/util.go b/util.go
index 0290adc..c46938d 100644
--- a/util.go
+++ b/util.go
@@ -21,9 +21,19 @@ func tryOptLogDirs(optLogDirs []string) (string, error) {
 	for i, d := range optLogDirs {
 		dir := fmt.Sprintf("%s/", d)
 		optionDirsStr += fmt.Sprintf("%d.[%s];", i, dir)
-		if _, err := os.Stat(dir); err == nil {
+		if ok := canWriteByTest(dir); ok {
 			return dir, nil
 		}
 	}
-	return "", fmt.Errorf("all optional dir are not exist: %s", optionDirsStr)
+	return "", fmt.Errorf("all optional dir are not exist or writeable: %s", optionDirsStr)
+}
+
+// canWriteByTest
+func canWriteByTest(dir string) bool {
+	testFile := filepath.Join(dir, ".write_test.log.tmp")
+	if err := os.WriteFile(testFile, []byte("test"), 0644); err != nil {
+		return false
+	}
+	os.Remove(testFile)
+	return true
 }
diff --git a/writer.go b/writer.go
index 83df903..982fa9e 100644
--- a/writer.go
+++ b/writer.go
@@ -35,22 +35,23 @@ func NewBaseWriter(logw, stdw, errw *os.File) *baseWriter {
 
 // OpenLogFile
 func (w *baseWriter) OpenLogFile(logDir, logName string, optLogDirs []string) {
+	realDir := ""
 	// Step 1. try get available log dir
-	if _, err := os.Stat(logDir); err == nil {
-		logDir = logDir
-	} else if dir, err := tryOptLogDirs(optLogDirs); err == nil {
-		logDir = dir
+	if _, err := os.Stat(logDir); err == nil && canWriteByTest(logDir) {
+		realDir = logDir
+	} else if dir, tryOptErr := tryOptLogDirs(optLogDirs); tryOptErr == nil {
+		realDir = dir
 	} else if err := os.Mkdir(logDir, 0755); err == nil {
-		logDir = logDir
+		realDir = logDir
 	} else {
-		errstr := fmt.Sprintf("all path not exist:\n "+
-			"a.[%s]\n b.[%s]\n c.[%s]\n",
-			logDir, "./log/", "./logs/")
+		errstr := fmt.Sprintf("all path not exist or writeable:\n "+
+			"logDir = %s, optLogDirs = %v\n",
+			logDir, optLogDirs)
 		panic("failed initlog:" + errstr)
 	}
 
 	// Step 2. open base writer logfile
-	filename := filepath.Join(logDir, logName+".log")
+	filename := filepath.Join(realDir, logName+".log")
 	w.logFilename = filename
 	w.logPreBackupTag = ""
 	w.ReopenLogFile()