1 files changed, 65 insertions, 10 deletions

diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 7bf4b1533f34..024085daab1a 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -99,8 +99,9 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
 	if (cgroup_on_dfl(to))
 		return -EINVAL;
 
-	if (!cgroup_may_migrate_to(to))
-		return -EBUSY;
+	ret = cgroup_migrate_vet_dst(to);
+	if (ret)
+		return ret;
 
 	mutex_lock(&cgroup_mutex);
 
@@ -121,7 +122,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
 	 * ->can_attach() fails.
 	 */
 	do {
-		css_task_iter_start(&from->self, &it);
+		css_task_iter_start(&from->self, 0, &it);
 		task = css_task_iter_next(&it);
 		if (task)
 			get_task_struct(task);
@@ -373,7 +374,7 @@ static int pidlist_array_load(struct cgroup *cgrp, enum cgroup_filetype type,
 	if (!array)
 		return -ENOMEM;
 	/* now, populate the array */
-	css_task_iter_start(&cgrp->self, &it);
+	css_task_iter_start(&cgrp->self, 0, &it);
 	while ((tsk = css_task_iter_next(&it))) {
 		if (unlikely(n == length))
 			break;
@@ -510,10 +511,58 @@ static int cgroup_pidlist_show(struct seq_file *s, void *v)
 	return 0;
 }
 
-static ssize_t cgroup_tasks_write(struct kernfs_open_file *of,
-				  char *buf, size_t nbytes, loff_t off)
+static ssize_t __cgroup1_procs_write(struct kernfs_open_file *of,
+				     char *buf, size_t nbytes, loff_t off,
+				     bool threadgroup)
 {
-	return __cgroup_procs_write(of, buf, nbytes, off, false);
+	struct cgroup *cgrp;
+	struct task_struct *task;
+	const struct cred *cred, *tcred;
+	ssize_t ret;
+
+	cgrp = cgroup_kn_lock_live(of->kn, false);
+	if (!cgrp)
+		return -ENODEV;
+
+	task = cgroup_procs_write_start(buf, threadgroup);
+	ret = PTR_ERR_OR_ZERO(task);
+	if (ret)
+		goto out_unlock;
+
+	/*
+	 * Even if we're attaching all tasks in the thread group, we only
+	 * need to check permissions on one of them.
+	 */
+	cred = current_cred();
+	tcred = get_task_cred(task);
+	if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) &&
+	    !uid_eq(cred->euid, tcred->uid) &&
+	    !uid_eq(cred->euid, tcred->suid))
+		ret = -EACCES;
+	put_cred(tcred);
+	if (ret)
+		goto out_finish;
+
+	ret = cgroup_attach_task(cgrp, task, threadgroup);
+
+out_finish:
+	cgroup_procs_write_finish(task);
+out_unlock:
+	cgroup_kn_unlock(of->kn);
+
+	return ret ?: nbytes;
+}
+
+static ssize_t cgroup1_procs_write(struct kernfs_open_file *of,
+				   char *buf, size_t nbytes, loff_t off)
+{
+	return __cgroup1_procs_write(of, buf, nbytes, off, true);
+}
+
+static ssize_t cgroup1_tasks_write(struct kernfs_open_file *of,
+				   char *buf, size_t nbytes, loff_t off)
+{
+	return __cgroup1_procs_write(of, buf, nbytes, off, false);
 }
 
 static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of,
@@ -592,7 +641,7 @@ struct cftype cgroup1_base_files[] = {
 		.seq_stop = cgroup_pidlist_stop,
 		.seq_show = cgroup_pidlist_show,
 		.private = CGROUP_FILE_PROCS,
-		.write = cgroup_procs_write,
+		.write = cgroup1_procs_write,
 	},
 	{
 		.name = "cgroup.clone_children",
@@ -611,7 +660,7 @@ struct cftype cgroup1_base_files[] = {
 		.seq_stop = cgroup_pidlist_stop,
 		.seq_show = cgroup_pidlist_show,
 		.private = CGROUP_FILE_TASKS,
-		.write = cgroup_tasks_write,
+		.write = cgroup1_tasks_write,
 	},
 	{
 		.name = "notify_on_release",
@@ -701,7 +750,7 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
 	}
 	rcu_read_unlock();
 
-	css_task_iter_start(&cgrp->self, &it);
+	css_task_iter_start(&cgrp->self, 0, &it);
 	while ((tsk = css_task_iter_next(&it))) {
 		switch (tsk->state) {
 		case TASK_RUNNING:
@@ -846,6 +895,8 @@ static int cgroup1_show_options(struct seq_file *seq, struct kernfs_root *kf_roo
 		seq_puts(seq, ",noprefix");
 	if (root->flags & CGRP_ROOT_XATTR)
 		seq_puts(seq, ",xattr");
+	if (root->flags & CGRP_ROOT_CPUSET_V2_MODE)
+		seq_puts(seq, ",cpuset_v2_mode");
 
 	spin_lock(&release_agent_path_lock);
 	if (strlen(root->release_agent_path))
@@ -900,6 +951,10 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
 			opts->cpuset_clone_children = true;
 			continue;
 		}
+		if (!strcmp(token, "cpuset_v2_mode")) {
+			opts->flags |= CGRP_ROOT_CPUSET_V2_MODE;
+			continue;
+		}
 		if (!strcmp(token, "xattr")) {
 			opts->flags |= CGRP_ROOT_XATTR;
 			continue;