fix: cancel all operations if c.V1Alpha2().Run fails

The current code contains a deadlock if `c.V1Alpha2().Run` fails with an error because `EnforceKSPPRequirements`
will indefinitely wait for a condition to happen, but the controller runtime is not running.
This commit addresses this by replacing the error channel with `context.WithCancelCause` and
canceling the context if the controller runner fails.

Signed-off-by: Dmitriy Matrenichev <dmitry.matrenichev@siderolabs.com>

internal/app/machined/main.go

@@ -35,6 +35,7 @@ import (
 	"github.com/siderolabs/talos/internal/app/poweroff"
 	"github.com/siderolabs/talos/internal/app/trustd"
 	"github.com/siderolabs/talos/internal/app/wrapperd"
+	"github.com/siderolabs/talos/internal/pkg/ctxutil"
 	"github.com/siderolabs/talos/internal/pkg/mount"
 	"github.com/siderolabs/talos/pkg/httpdefaults"
 	"github.com/siderolabs/talos/pkg/machinery/api/common"
@@ -163,8 +164,6 @@ func runDebugServer(ctx context.Context) {
 
 //nolint:gocyclo
 func run() error {
-	errCh := make(chan error)
-
 	// Limit GOMAXPROCS.
 	startup.LimitMaxProcs(constants.MachinedMaxProcs)
 
@@ -179,8 +178,8 @@ func run() error {
 		return err
 	}
 
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
+	ctx, cancel := context.WithCancelCause(context.Background())
+	defer cancel(nil)
 
 	drainer := runtime.NewDrainer()
 	defer func() {
@@ -207,7 +206,7 @@ func run() error {
 	// Start v2 controller runtime.
 	go func() {
 		if e := c.V1Alpha2().Run(ctx, drainer); e != nil {
-			errCh <- fmt.Errorf("fatal controller runtime error: %s", e)
+			cancel(fmt.Errorf("fatal controller runtime error: %s", e))
 		}
 
 		log.Printf("controller runtime finished")
@@ -265,21 +264,21 @@ func run() error {
 								continue
 							}
 
-							errCh <- fmt.Errorf(
+							cancel(fmt.Errorf(
 								"fatal sequencer error in %q sequence: %v",
 								msg.GetSequence(),
 								msg.GetError().String(),
-							)
+							))
 						}
 					case *machine.RestartEvent:
-						errCh <- runtime.RebootError{Cmd: int(msg.Cmd)}
+						cancel(runtime.RebootError{Cmd: int(msg.Cmd)})
 					}
 				}
 			}
 		},
 	)
 
-	return <-errCh
+	return ctxutil.Cause(ctx)
 }
 
 func main() {