diff --git a/qemu/qemu-kernel.go b/qemu/qemu-kernel.go
index 7462798..c0d0ad9 100644
--- a/qemu/qemu-kernel.go
+++ b/qemu/qemu-kernel.go
@@ -15,6 +15,7 @@ import (
 	"os/exec"
 	"runtime"
 	"strings"
+	"sync"
 	"syscall"
 	"time"
 
@@ -364,7 +365,12 @@ func (q System) WaitForSSH(timeout time.Duration) error {
 	return errors.New("no ssh (timeout)")
 }
 
+var sshMu sync.Mutex
+
 func (q System) ssh(user string) (client *ssh.Client, err error) {
+	sshMu.Lock()
+	defer sshMu.Unlock()
+
 	cfg := &ssh.ClientConfig{
 		User:            user,
 		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
@@ -464,7 +470,9 @@ func (q System) scp(user, localPath, remotePath string, recursive bool) (err err
 		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
 	}
 
+	sshMu.Lock()
 	client, err := scp.NewClient(q.sshAddrPort, cfg, &scp.ClientOption{})
+	sshMu.Unlock()
 	if err != nil {
 		return
 	}