runtime: fix duplicated devices requested to the agent

By default, when a container is created with the `--privileged` flag,
all devices in `/dev` from the host are mounted into the guest. If
there is a block device(e.g. `/dev/dm`) followed by a generic
device(e.g. `/dev/null`)，two identical block devices(`/dev/dm`)
would be requested to the kata agent causing the agent to exit with error:

> Conflicting device updates for /dev/dm-2

As the generic device type does not hit any cases defined in `switch`，
the variable `kataDevice` which is defined outside of the loop is still
the value of the previous block device rather than `nil`. Defining `kataDevice`
in the loop fixes this bug.

Signed-off-by: cncal <flycalvin@qq.com>

src/runtime/virtcontainers/kata_agent.go

@@ -6,6 +6,7 @@
 package virtcontainers
 
 import (
+	"context"
 	b64 "encoding/base64"
 	"encoding/json"
 	"errors"
@@ -34,8 +35,6 @@ import (
 	"github.com/kata-containers/kata-containers/src/runtime/virtcontainers/types"
 	"github.com/kata-containers/kata-containers/src/runtime/virtcontainers/utils"
 
-	"context"
-
 	ctrAnnotations "github.com/containerd/containerd/pkg/cri/annotations"
 	podmanAnnotations "github.com/containers/podman/v4/pkg/annotations"
 	"github.com/opencontainers/runtime-spec/specs-go"
@@ -1200,8 +1199,6 @@ func (k *kataAgent) appendVfioDevice(dev ContainerDevice, device api.Device, c *
 }
 
 func (k *kataAgent) appendDevices(deviceList []*grpc.Device, c *Container) []*grpc.Device {
-	var kataDevice *grpc.Device
-
 	for _, dev := range c.devices {
 		device := c.sandbox.devManager.GetDeviceByID(dev.ID)
 		if device == nil {
@@ -1213,6 +1210,8 @@ func (k *kataAgent) appendDevices(deviceList []*grpc.Device, c *Container) []*gr
 			continue
 		}
 
+		var kataDevice *grpc.Device
+
 		switch device.DeviceType() {
 		case config.DeviceBlock:
 			kataDevice = k.appendBlockDevice(dev, device, c)

src/runtime/virtcontainers/kata_agent_test.go

@@ -479,16 +479,21 @@ func TestAppendDevicesEmptyContainerDeviceList(t *testing.T) {
 func TestAppendDevices(t *testing.T) {
 	k := kataAgent{}
 
-	id := "test-append-block"
+	testBlockDeviceID := "test-block-device"
+	testCharacterDeviceId := "test-character-device"
+
 	ctrDevices := []api.Device{
 		&drivers.BlockDevice{
 			GenericDevice: &drivers.GenericDevice{
-				ID: id,
+				ID: testBlockDeviceID,
 			},
 			BlockDrive: &config.BlockDrive{
 				PCIPath: testPCIPath,
 			},
 		},
+		&drivers.GenericDevice{
+			ID: testCharacterDeviceId,
+		},
 	}
 
 	sandboxConfig := &SandboxConfig{
@@ -503,10 +508,16 @@ func TestAppendDevices(t *testing.T) {
 			config:     sandboxConfig,
 		},
 	}
-	c.devices = append(c.devices, ContainerDevice{
-		ID:            id,
-		ContainerPath: testBlockDeviceCtrPath,
-	})
+	c.devices = append(
+		c.devices,
+		ContainerDevice{
+			ID:            testBlockDeviceID,
+			ContainerPath: testBlockDeviceCtrPath,
+		},
+		ContainerDevice{
+			ID: testCharacterDeviceId,
+		},
+	)
 
 	devList := []*pb.Device{}
 	expected := []*pb.Device{