Merge pull request #228 from jseba/delete_empty_cgroups_only

Kazuyoshi Kato · web-flow · commit e3fea41ea2ae · 2022-10-17T15:46:09.000-07:00
Check that cgroup is empty before deleting
diff --git a/cgroup.go b/cgroup.go
@@ -84,7 +84,7 @@ func Load(hierarchy Hierarchy, path Path, opts ...InitOpts) (Cgroup, error) {
 	for _, s := range pathers(subsystems) {
 		p, err := path(s.Name())
 		if err != nil {
-			if  errors.Is(err, os.ErrNotExist) {
+			if errors.Is(err, os.ErrNotExist) {
 				return nil, ErrCgroupDeleted
 			}
 			if err == ErrControllerNotActive {
@@ -228,6 +228,15 @@ func (c *cgroup) Delete() error {
 	}
 	var errs []string
 	for _, s := range c.subsystems {
+		// kernel prevents cgroups with running process from being removed, check the tree is empty
+		procs, err := c.processes(s.Name(), true, cgroupProcs)
+		if err != nil {
+			return err
+		}
+		if len(procs) > 0 {
+			errs = append(errs, fmt.Sprintf("%s (contains running processes)", string(s.Name())))
+			continue
+		}
 		if d, ok := s.(deleter); ok {
 			sp, err := c.path(s.Name())
 			if err != nil {
@@ -247,6 +256,7 @@ func (c *cgroup) Delete() error {
 			if err := remove(path); err != nil {
 				errs = append(errs, path)
 			}
+			continue
 		}
 	}
 	if len(errs) > 0 {
diff --git a/v2/manager.go b/v2/manager.go
@@ -345,6 +345,14 @@ func (c *Manager) AddThread(tid uint64) error {
 }
 
 func (c *Manager) Delete() error {
+	// kernel prevents cgroups with running process from being removed, check the tree is empty
+	processes, err := c.Procs(true)
+	if err != nil {
+		return err
+	}
+	if len(processes) > 0 {
+		return fmt.Errorf("cgroups: unable to remove path %q: still contains running processes", c.path)
+	}
 	return remove(c.path)
 }
 

Original file line number	Diff line number	Diff line change
`@@ -345,6 +345,14 @@ func (c *Manager) AddThread(tid uint64) error {`
`345`	`345`	`}`
`346`	`346`
`347`	`347`	`func (c *Manager) Delete() error {`
	`348`	`+ // kernel prevents cgroups with running process from being removed, check the tree is empty`
	`349`	`+ processes, err := c.Procs(true)`
	`350`	`+ if err != nil {`
	`351`	`+ return err`
	`352`	`+ }`
	`353`	`+ if len(processes) > 0 {`
	`354`	`+ return fmt.Errorf("cgroups: unable to remove path %q: still contains running processes", c.path)`
	`355`	`+ }`
`348`	`356`	`return remove(c.path)`
`349`	`357`	`}`
`350`	`358`