diff --git a/hack/buildkit-ref b/hack/buildkit-ref
index 8e6577f7b0..1936d009bd 100755
--- a/hack/buildkit-ref
+++ b/hack/buildkit-ref
@@ -19,6 +19,9 @@ if [[ "${buildkit_ref}" == *-*-* ]]; then
 	buildkit_ref=$(curl -s "https://api.github.com/repos/${buildkit_repo}/commits/${buildkit_ref}" | jq -r .sha)
 fi
 
+# https://github.com/moby/buildkit/pull/6278
+buildkit_ref="1030099b27bd3455bf7e5d5fe73b6be5dbec3c1f"
+
 cat << EOF
 BUILDKIT_REPO=$buildkit_repo
 BUILDKIT_REF=$buildkit_ref
diff --git a/hack/cpexp/cpexp.go b/hack/cpexp/cpexp.go
new file mode 100644
index 0000000000..c58d062871
--- /dev/null
+++ b/hack/cpexp/cpexp.go
@@ -0,0 +1,127 @@
+package main
+
+import (
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/moby/buildkit/identity"
+	"github.com/moby/sys/mountinfo"
+	"github.com/pkg/errors"
+)
+
+const volumePath = "/abc/a"
+
+var rootfs string
+
+func main() {
+	if err := run(); err != nil {
+		log.Printf("error: %+v", err)
+	}
+}
+
+func run() error {
+	infos, err := mountinfo.GetMounts(nil)
+	if err != nil {
+		return err
+	}
+	hasVolume := false
+	for _, info := range infos {
+		if info.Mountpoint == "/" {
+			v, err := getOverlayRootfs(info)
+			if err != nil {
+				return err
+			}
+			rootfs = v
+		}
+
+		if info.Mountpoint == volumePath {
+			hasVolume = true
+		}
+		log.Printf("mount: %+v", info)
+	}
+	if !hasVolume {
+		return errors.Errorf("volume not found: %s", volumePath)
+	}
+
+	log.Printf("rootfs: %s", rootfs)
+
+	base := filepath.Base(rootfs)
+	if err := os.Symlink("/", filepath.Join(volumePath, base)); err != nil {
+		return err
+	}
+
+	// create duplicate volume path with symlink target
+	p := "/"
+	var volumeRoot string
+	for _, c := range strings.Split(filepath.Dir(volumePath), string(filepath.Separator)) {
+		if c == "" {
+			continue
+		}
+		if volumeRoot == "" {
+			volumeRoot = "/" + c
+			c += "_target"
+		}
+		p = filepath.Join(p, c)
+		if err := os.Mkdir(p, 0755); err != nil {
+			if os.IsExist(err) {
+				continue
+			}
+			return err
+		}
+		log.Printf("created: %s", p)
+	}
+	if err := os.Symlink(filepath.Dir(rootfs), filepath.Join(p, filepath.Base(volumePath))); err != nil {
+		return err
+	}
+
+	if err := os.Rename(volumeRoot, volumeRoot+"_old"); err != nil {
+		return err
+	}
+
+	for {
+		if _, err := os.Stat(volumeRoot); err != nil {
+			if os.IsNotExist(err) {
+				continue
+			}
+			return err
+		}
+		// log.Printf("detected: %s", volumeRoot)
+		break
+	}
+
+	for {
+		if err := os.Rename(volumeRoot+"_target", volumeRoot); err != nil {
+			if os.IsExist(err) {
+				if err := os.Rename(volumeRoot, volumeRoot+"_"+identity.NewID()); err != nil {
+					return err
+				}
+				continue
+			}
+			log.Printf("failed to rename: %s", err)
+		}
+		break
+	}
+
+	return nil
+}
+
+func getOverlayRootfs(info *mountinfo.Info) (string, error) {
+	if info.FSType != "overlay" {
+		return "", errors.Errorf("not overlay: %s", info.FSType)
+	}
+	for _, opt := range strings.Split(info.VFSOptions, ",") {
+		parts := strings.SplitN(opt, "=", 2)
+		if parts[0] == "workdir" {
+			return filepath.Join(filepath.Dir(parts[1]), "merged"), nil
+		}
+	}
+	return "", errors.Errorf("workdir not found: %s", info.VFSOptions)
+}
+
+// /var/lib/docker/overlay2/86fcb18db0e3774cfe3b9ed6fa526d4dffcb45ac3b26cbe99db6c2d08e6dfc0e/merged
+
+// merged/<sym>/dir1/dir2/
+
+// volume