Revert "Merge pull request 101888 from kolyshkin/update-runc-rc94"

This reverts commit b1b06fe0a4, reversing
changes made to 382a33986b.

vendor/github.com/cilium/ebpf/internal/feature.go

@@ -32,7 +32,7 @@ func (ufe *UnsupportedFeatureError) Is(target error) bool {
 }
 
 type featureTest struct {
-	sync.RWMutex
+	sync.Mutex
 	successful bool
 	result     error
 }
@@ -42,10 +42,10 @@ type featureTest struct {
 //
 // The return values have the following semantics:
 //
-//   err == ErrNotSupported: the feature is not available
-//   err == nil: the feature is available
 //   err != nil: the test couldn't be executed
-type FeatureTestFn func() error
+//   err == nil && available: the feature is available
+//   err == nil && !available: the feature isn't available
+type FeatureTestFn func() (available bool, err error)
 
 // FeatureTest wraps a function so that it is run at most once.
 //
@@ -61,40 +61,70 @@ func FeatureTest(name, version string, fn FeatureTestFn) func() error {
 
 	ft := new(featureTest)
 	return func() error {
-		ft.RLock()
-		if ft.successful {
-			defer ft.RUnlock()
-			return ft.result
-		}
-		ft.RUnlock()
 		ft.Lock()
 		defer ft.Unlock()
-		// check one more time on the off
-		// chance that two go routines
-		// were able to call into the write
-		// lock
+
 		if ft.successful {
 			return ft.result
 		}
-		err := fn()
-		switch {
-		case errors.Is(err, ErrNotSupported):
+
+		available, err := fn()
+		if errors.Is(err, ErrNotSupported) {
+			// The feature test aborted because a dependent feature
+			// is missing, which we should cache.
+			available = false
+		} else if err != nil {
+			// We couldn't execute the feature test to a point
+			// where it could make a determination.
+			// Don't cache the result, just return it.
+			return fmt.Errorf("can't detect support for %s: %w", name, err)
+		}
+
+		ft.successful = true
+		if !available {
 			ft.result = &UnsupportedFeatureError{
 				MinimumVersion: v,
 				Name:           name,
 			}
-			fallthrough
-
-		case err == nil:
-			ft.successful = true
-
-		default:
-			// We couldn't execute the feature test to a point
-			// where it could make a determination.
-			// Don't cache the result, just return it.
-			return fmt.Errorf("detect support for %s: %w", name, err)
 		}
-
 		return ft.result
 	}
 }
+
+// A Version in the form Major.Minor.Patch.
+type Version [3]uint16
+
+// NewVersion creates a version from a string like "Major.Minor.Patch".
+//
+// Patch is optional.
+func NewVersion(ver string) (Version, error) {
+	var major, minor, patch uint16
+	n, _ := fmt.Sscanf(ver, "%d.%d.%d", &major, &minor, &patch)
+	if n < 2 {
+		return Version{}, fmt.Errorf("invalid version: %s", ver)
+	}
+	return Version{major, minor, patch}, nil
+}
+
+func (v Version) String() string {
+	if v[2] == 0 {
+		return fmt.Sprintf("v%d.%d", v[0], v[1])
+	}
+	return fmt.Sprintf("v%d.%d.%d", v[0], v[1], v[2])
+}
+
+// Less returns true if the version is less than another version.
+func (v Version) Less(other Version) bool {
+	for i, a := range v {
+		if a == other[i] {
+			continue
+		}
+		return a < other[i]
+	}
+	return false
+}
+
+// Unspecified returns true if the version is all zero.
+func (v Version) Unspecified() bool {
+	return v[0] == 0 && v[1] == 0 && v[2] == 0
+}