diff --git a/libcontainer/configs/validate/validator.go b/libcontainer/configs/validate/validator.go
index 483e7a2ff..26e137901 100644
--- a/libcontainer/configs/validate/validator.go
+++ b/libcontainer/configs/validate/validator.go
@@ -12,7 +12,6 @@ import (
 	"github.com/opencontainers/runc/libcontainer/configs"
 	"github.com/opencontainers/runc/libcontainer/intelrdt"
 	selinux "github.com/opencontainers/selinux/go-selinux"
-	"github.com/sirupsen/logrus"
 	"golang.org/x/sys/unix"
 )
 
@@ -29,21 +28,13 @@ func Validate(config *configs.Config) error {
 		sysctl,
 		intelrdtCheck,
 		rootlessEUIDCheck,
+		mounts,
 	}
 	for _, c := range checks {
 		if err := c(config); err != nil {
 			return err
 		}
 	}
-	// Relaxed validation rules for backward compatibility
-	warns := []check{
-		mounts, // TODO (runc v1.x.x): make this an error instead of a warning
-	}
-	for _, c := range warns {
-		if err := c(config); err != nil {
-			logrus.WithError(err).Warn("invalid configuration")
-		}
-	}
 	return nil
 }
 
diff --git a/libcontainer/configs/validate/validator_test.go b/libcontainer/configs/validate/validator_test.go
index f59d0f203..ad632c89f 100644
--- a/libcontainer/configs/validate/validator_test.go
+++ b/libcontainer/configs/validate/validator_test.go
@@ -360,11 +360,10 @@ func TestValidateMounts(t *testing.T) {
 		isErr bool
 		dest  string
 	}{
-		// TODO (runc v1.x.x): make these relative paths an error. See https://github.com/opencontainers/runc/pull/3004
-		{isErr: false, dest: "not/an/abs/path"},
-		{isErr: false, dest: "./rel/path"},
-		{isErr: false, dest: "./rel/path"},
-		{isErr: false, dest: "../../path"},
+		{isErr: true, dest: "not/an/abs/path"},
+		{isErr: true, dest: "./rel/path"},
+		{isErr: true, dest: "./rel/path"},
+		{isErr: true, dest: "../../path"},
 
 		{isErr: false, dest: "/abs/path"},
 		{isErr: false, dest: "/abs/but/../unclean"},