Ensure safety before reuse of pipe

checker_linux.go

@@ -177,7 +177,10 @@ func (c *Checker) CheckAddrZeroLinger(addr string, timeout time.Duration, zeroLi
 func (c *Checker) waitConnectResult(fd int, timeout time.Duration) error {
 	// get a pipe of connect result
 	resultPipe := c.getPipe()
-	defer c.putBackPipe(resultPipe)
+	defer func() {
+		c.deregisterResultPipe(fd)
+		c.putBackPipe(resultPipe)
+	}()
 
 	// this must be done before registerEvents
 	c.registerResultPipe(fd, resultPipe)
@@ -190,6 +193,10 @@ func (c *Checker) waitConnectResult(fd int, timeout time.Duration) error {
 	return c.waitPipeTimeout(resultPipe, timeout)
 }
 
+func (c *Checker) deregisterResultPipe(fd int) {
+	c.fdResultPipes.Delete(fd)
+}
+
 func (c *Checker) registerResultPipe(fd int, pipe chan error) {
 	// NOTE: the pipe should have been put back if c.fdResultPipes[fd] exists.
 	c.fdResultPipes.Store(fd, pipe)

pipe_pool.go

@@ -19,5 +19,13 @@ func (p *pipePool) getPipe() chan error {
 }
 
 func (p *pipePool) putBackPipe(pipe chan error) {
+	p.cleanPipe(pipe)
 	p.pool.Put(pipe)
 }
+
+func (p *pipePool) cleanPipe(pipe chan error) {
+	select {
+	case <-pipe:
+	default:
+	}
+}