rebase: update replaced k8s.io modules to v0.33.0

Signed-off-by: Niels de Vos <ndevos@ibm.com>

e2e/vendor/github.com/opencontainers/cgroups/fs/freezer.go

@@ -0,0 +1,157 @@
+package fs
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/opencontainers/cgroups"
+	"github.com/sirupsen/logrus"
+	"golang.org/x/sys/unix"
+)
+
+type FreezerGroup struct{}
+
+func (s *FreezerGroup) Name() string {
+	return "freezer"
+}
+
+func (s *FreezerGroup) Apply(path string, _ *cgroups.Resources, pid int) error {
+	return apply(path, pid)
+}
+
+func (s *FreezerGroup) Set(path string, r *cgroups.Resources) (Err error) {
+	switch r.Freezer {
+	case cgroups.Frozen:
+		defer func() {
+			if Err != nil {
+				// Freezing failed, and it is bad and dangerous
+				// to leave the cgroup in FROZEN or FREEZING
+				// state, so (try to) thaw it back.
+				_ = cgroups.WriteFile(path, "freezer.state", string(cgroups.Thawed))
+			}
+		}()
+
+		// As per older kernel docs (freezer-subsystem.txt before
+		// kernel commit ef9fe980c6fcc1821), if FREEZING is seen,
+		// userspace should either retry or thaw. While current
+		// kernel cgroup v1 docs no longer mention a need to retry,
+		// even a recent kernel (v5.4, Ubuntu 20.04) can't reliably
+		// freeze a cgroup v1 while new processes keep appearing in it
+		// (either via fork/clone or by writing new PIDs to
+		// cgroup.procs).
+		//
+		// The numbers below are empirically chosen to have a decent
+		// chance to succeed in various scenarios ("runc pause/unpause
+		// with parallel runc exec" and "bare freeze/unfreeze on a very
+		// slow system"), tested on RHEL7 and Ubuntu 20.04 kernels.
+		//
+		// Adding any amount of sleep in between retries did not
+		// increase the chances of successful freeze in "pause/unpause
+		// with parallel exec" reproducer. OTOH, adding an occasional
+		// sleep helped for the case where the system is extremely slow
+		// (CentOS 7 VM on GHA CI).
+		//
+		// Alas, this is still a game of chances, since the real fix
+		// belong to the kernel (cgroup v2 do not have this bug).
+
+		for i := 0; i < 1000; i++ {
+			if i%50 == 49 {
+				// Occasional thaw and sleep improves
+				// the chances to succeed in freezing
+				// in case new processes keep appearing
+				// in the cgroup.
+				_ = cgroups.WriteFile(path, "freezer.state", string(cgroups.Thawed))
+				time.Sleep(10 * time.Millisecond)
+			}
+
+			if err := cgroups.WriteFile(path, "freezer.state", string(cgroups.Frozen)); err != nil {
+				return err
+			}
+
+			if i%25 == 24 {
+				// Occasional short sleep before reading
+				// the state back also improves the chances to
+				// succeed in freezing in case of a very slow
+				// system.
+				time.Sleep(10 * time.Microsecond)
+			}
+			state, err := cgroups.ReadFile(path, "freezer.state")
+			if err != nil {
+				return err
+			}
+			state = strings.TrimSpace(state)
+			switch state {
+			case "FREEZING":
+				continue
+			case string(cgroups.Frozen):
+				if i > 1 {
+					logrus.Debugf("frozen after %d retries", i)
+				}
+				return nil
+			default:
+				// should never happen
+				return fmt.Errorf("unexpected state %s while freezing", strings.TrimSpace(state))
+			}
+		}
+		// Despite our best efforts, it got stuck in FREEZING.
+		return errors.New("unable to freeze")
+	case cgroups.Thawed:
+		return cgroups.WriteFile(path, "freezer.state", string(cgroups.Thawed))
+	case cgroups.Undefined:
+		return nil
+	default:
+		return fmt.Errorf("Invalid argument '%s' to freezer.state", string(r.Freezer))
+	}
+}
+
+func (s *FreezerGroup) GetStats(path string, stats *cgroups.Stats) error {
+	return nil
+}
+
+func (s *FreezerGroup) GetState(path string) (cgroups.FreezerState, error) {
+	for {
+		state, err := cgroups.ReadFile(path, "freezer.state")
+		if err != nil {
+			// If the kernel is too old, then we just treat the freezer as
+			// being in an "undefined" state.
+			if os.IsNotExist(err) || errors.Is(err, unix.ENODEV) {
+				err = nil
+			}
+			return cgroups.Undefined, err
+		}
+		switch strings.TrimSpace(state) {
+		case "THAWED":
+			return cgroups.Thawed, nil
+		case "FROZEN":
+			// Find out whether the cgroup is frozen directly,
+			// or indirectly via an ancestor.
+			self, err := cgroups.ReadFile(path, "freezer.self_freezing")
+			if err != nil {
+				// If the kernel is too old, then we just treat
+				// it as being frozen.
+				if errors.Is(err, os.ErrNotExist) || errors.Is(err, unix.ENODEV) {
+					err = nil
+				}
+				return cgroups.Frozen, err
+			}
+			switch self {
+			case "0\n":
+				return cgroups.Thawed, nil
+			case "1\n":
+				return cgroups.Frozen, nil
+			default:
+				return cgroups.Undefined, fmt.Errorf(`unknown "freezer.self_freezing" state: %q`, self)
+			}
+		case "FREEZING":
+			// Make sure we get a stable freezer state, so retry if the cgroup
+			// is still undergoing freezing. This should be a temporary delay.
+			time.Sleep(1 * time.Millisecond)
+			continue
+		default:
+			return cgroups.Undefined, fmt.Errorf("unknown freezer.state %q", state)
+		}
+	}
+}