3 files changed, 16 insertions, 23 deletions

diff --git a/pkg/cgroups/cgroups.go b/pkg/cgroups/cgroups.go
index f23787bd4..0d7ed05b2 100644
--- a/pkg/cgroups/cgroups.go
+++ b/pkg/cgroups/cgroups.go
@@ -2,6 +2,7 @@ package cgroups
 
 import (
 	"bufio"
+	"bytes"
 	"fmt"
 	"io/ioutil"
 	"math"
@@ -131,7 +132,7 @@ func getAvailableControllers(exclude map[string]controllerHandler, cgroup2 bool)
 
 	infos, err := ioutil.ReadDir(cgroupRoot)
 	if err != nil {
-		return nil, errors.Wrapf(err, "read directory %s", cgroupRoot)
+		return nil, err
 	}
 	controllers := []controller{}
 	for _, i := range infos {
@@ -155,23 +156,15 @@ func (c *CgroupControl) getCgroupv1Path(name string) string {
 
 // createCgroupv2Path creates the cgroupv2 path and enables all the available controllers
 func createCgroupv2Path(path string) (deferredError error) {
-	content, err := ioutil.ReadFile("/sys/fs/cgroup/cgroup.controllers")
-	if err != nil {
-		return errors.Wrapf(err, "read /sys/fs/cgroup/cgroup.controllers")
-	}
-	if !strings.HasPrefix(path, "/sys/fs/cgroup/") {
+	if !strings.HasPrefix(path, cgroupRoot+"/") {
 		return fmt.Errorf("invalid cgroup path %s", path)
 	}
-
-	res := ""
-	for i, c := range strings.Split(strings.TrimSpace(string(content)), " ") {
-		if i == 0 {
-			res = fmt.Sprintf("+%s", c)
-		} else {
-			res += fmt.Sprintf(" +%s", c)
-		}
+	content, err := ioutil.ReadFile(cgroupRoot + "/cgroup.controllers")
+	if err != nil {
+		return err
 	}
-	resByte := []byte(res)
+	ctrs := bytes.Fields(content)
+	res := append([]byte("+"), bytes.Join(ctrs, []byte(" +"))...)
 
 	current := "/sys/fs"
 	elements := strings.Split(path, "/")
@@ -180,7 +173,7 @@ func createCgroupv2Path(path string) (deferredError error) {
 		if i > 0 {
 			if err := os.Mkdir(current, 0755); err != nil {
 				if !os.IsExist(err) {
-					return errors.Wrapf(err, "mkdir %s", path)
+					return err
 				}
 			} else {
 				// If the directory was created, be sure it is not left around on errors.
@@ -194,8 +187,8 @@ func createCgroupv2Path(path string) (deferredError error) {
 		// We enable the controllers for all the path components except the last one.  It is not allowed to add
 		// PIDs if there are already enabled controllers.
 		if i < len(elements[3:])-1 {
-			if err := ioutil.WriteFile(filepath.Join(current, "cgroup.subtree_control"), resByte, 0755); err != nil {
-				return errors.Wrapf(err, "write %s", filepath.Join(current, "cgroup.subtree_control"))
+			if err := ioutil.WriteFile(filepath.Join(current, "cgroup.subtree_control"), res, 0755); err != nil {
+				return err
 			}
 		}
 	}
@@ -237,7 +230,7 @@ func (c *CgroupControl) initialize() (err error) {
 			}
 			path := c.getCgroupv1Path(ctr.name)
 			if err := os.MkdirAll(path, 0755); err != nil {
-				return errors.Wrapf(err, "error creating cgroup path %s for %s", path, ctr.name)
+				return errors.Wrapf(err, "error creating cgroup path for %s", ctr.name)
 			}
 		}
 	}
@@ -265,7 +258,7 @@ func (c *CgroupControl) createCgroupDirectory(controller string) (bool, error) {
 func readFileAsUint64(path string) (uint64, error) {
 	data, err := ioutil.ReadFile(path)
 	if err != nil {
-		return 0, errors.Wrapf(err, "open %s", path)
+		return 0, err
 	}
 	v := cleanString(string(data))
 	if v == "max" {
@@ -425,7 +418,7 @@ func rmDirRecursively(path string) error {
 	}
 	entries, err := ioutil.ReadDir(path)
 	if err != nil {
-		return errors.Wrapf(err, "read %s", path)
+		return err
 	}
 	for _, i := range entries {
 		if i.IsDir() {
diff --git a/pkg/cgroups/cgroups_supported.go b/pkg/cgroups/cgroups_supported.go
index a9fef38b9..fe17db7f7 100644
--- a/pkg/cgroups/cgroups_supported.go
+++ b/pkg/cgroups/cgroups_supported.go
@@ -46,7 +46,7 @@ func UserOwnsCurrentSystemdCgroup() (bool, error) {
 
 	f, err := os.Open("/proc/self/cgroup")
 	if err != nil {
-		return false, errors.Wrapf(err, "open file /proc/self/cgroup")
+		return false, err
 	}
 	defer f.Close()
 
diff --git a/pkg/cgroups/cpu.go b/pkg/cgroups/cpu.go
index 3745c6e50..a73187dc8 100644
--- a/pkg/cgroups/cpu.go
+++ b/pkg/cgroups/cpu.go
@@ -134,7 +134,7 @@ func GetSystemCPUUsage() (uint64, error) {
 
 	files, err := ioutil.ReadDir(cgroupRoot)
 	if err != nil {
-		return 0, errors.Wrapf(err, "read directory %q", cgroupRoot)
+		return 0, err
 	}
 	var total uint64
 	for _, file := range files {