1 files changed, 47 insertions, 39 deletions

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 935e8121b21e..625d7483951c 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1391,7 +1391,7 @@ static void cgroup_destroy_root(struct cgroup_root *root)
 	cgroup_favor_dynmods(root, false);
 	cgroup_exit_root_id(root);
 
-	mutex_unlock(&cgroup_mutex);
+	cgroup_unlock();
 
 	cgroup_rstat_exit(cgrp);
 	kernfs_destroy_root(root->kf_root);
@@ -1465,8 +1465,18 @@ static struct cgroup *current_cgns_cgroup_dfl(void)
 {
 	struct css_set *cset;
 
-	cset = current->nsproxy->cgroup_ns->root_cset;
-	return __cset_cgroup_from_root(cset, &cgrp_dfl_root);
+	if (current->nsproxy) {
+		cset = current->nsproxy->cgroup_ns->root_cset;
+		return __cset_cgroup_from_root(cset, &cgrp_dfl_root);
+	} else {
+		/*
+		 * NOTE: This function may be called from bpf_cgroup_from_id()
+		 * on a task which has already passed exit_task_namespaces() and
+		 * nsproxy == NULL. Fall back to cgrp_dfl_root which will make all
+		 * cgroups visible for lookups.
+		 */
+		return &cgrp_dfl_root.cgrp;
+	}
 }
 
 /* look up cgroup associated with given css_set on the specified hierarchy */
@@ -1625,7 +1635,7 @@ void cgroup_kn_unlock(struct kernfs_node *kn)
 	else
 		cgrp = kn->parent->priv;
 
-	mutex_unlock(&cgroup_mutex);
+	cgroup_unlock();
 
 	kernfs_unbreak_active_protection(kn);
 	cgroup_put(cgrp);
@@ -1670,7 +1680,7 @@ struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline)
 	if (drain_offline)
 		cgroup_lock_and_drain_offline(cgrp);
 	else
-		mutex_lock(&cgroup_mutex);
+		cgroup_lock();
 
 	if (!cgroup_is_dead(cgrp))
 		return cgrp;
@@ -2167,13 +2177,13 @@ int cgroup_do_get_tree(struct fs_context *fc)
 		struct super_block *sb = fc->root->d_sb;
 		struct cgroup *cgrp;
 
-		mutex_lock(&cgroup_mutex);
+		cgroup_lock();
 		spin_lock_irq(&css_set_lock);
 
 		cgrp = cset_cgroup_from_root(ctx->ns->root_cset, ctx->root);
 
 		spin_unlock_irq(&css_set_lock);
-		mutex_unlock(&cgroup_mutex);
+		cgroup_unlock();
 
 		nsdentry = kernfs_node_dentry(cgrp->kn, sb);
 		dput(fc->root);
@@ -2356,13 +2366,13 @@ int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
 {
 	int ret;
 
-	mutex_lock(&cgroup_mutex);
+	cgroup_lock();
 	spin_lock_irq(&css_set_lock);
 
 	ret = cgroup_path_ns_locked(cgrp, buf, buflen, ns);
 
 	spin_unlock_irq(&css_set_lock);
-	mutex_unlock(&cgroup_mutex);
+	cgroup_unlock();
 
 	return ret;
 }
@@ -2388,7 +2398,7 @@ int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
 	int hierarchy_id = 1;
 	int ret;
 
-	mutex_lock(&cgroup_mutex);
+	cgroup_lock();
 	spin_lock_irq(&css_set_lock);
 
 	root = idr_get_next(&cgroup_hierarchy_idr, &hierarchy_id);
@@ -2402,7 +2412,7 @@ int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
 	}
 
 	spin_unlock_irq(&css_set_lock);
-	mutex_unlock(&cgroup_mutex);
+	cgroup_unlock();
 	return ret;
 }
 EXPORT_SYMBOL_GPL(task_cgroup_path);
@@ -3111,7 +3121,7 @@ void cgroup_lock_and_drain_offline(struct cgroup *cgrp)
 	int ssid;
 
 restart:
-	mutex_lock(&cgroup_mutex);
+	cgroup_lock();
 
 	cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) {
 		for_each_subsys(ss, ssid) {
@@ -3125,7 +3135,7 @@ restart:
 			prepare_to_wait(&dsct->offline_waitq, &wait,
 					TASK_UNINTERRUPTIBLE);
 
-			mutex_unlock(&cgroup_mutex);
+			cgroup_unlock();
 			schedule();
 			finish_wait(&dsct->offline_waitq, &wait);
 
@@ -3761,7 +3771,7 @@ static ssize_t pressure_write(struct kernfs_open_file *of, char *buf,
 	}
 
 	psi = cgroup_psi(cgrp);
-	new = psi_trigger_create(psi, buf, res);
+	new = psi_trigger_create(psi, buf, res, of->file);
 	if (IS_ERR(new)) {
 		cgroup_put(cgrp);
 		return PTR_ERR(new);
@@ -4374,9 +4384,9 @@ int cgroup_rm_cftypes(struct cftype *cfts)
 	if (!(cfts[0].flags & __CFTYPE_ADDED))
 		return -ENOENT;
 
-	mutex_lock(&cgroup_mutex);
+	cgroup_lock();
 	ret = cgroup_rm_cftypes_locked(cfts);
-	mutex_unlock(&cgroup_mutex);
+	cgroup_unlock();
 	return ret;
 }
 
@@ -4408,14 +4418,14 @@ static int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
 	if (ret)
 		return ret;
 
-	mutex_lock(&cgroup_mutex);
+	cgroup_lock();
 
 	list_add_tail(&cfts->node, &ss->cfts);
 	ret = cgroup_apply_cftypes(cfts, true);
 	if (ret)
 		cgroup_rm_cftypes_locked(cfts);
 
-	mutex_unlock(&cgroup_mutex);
+	cgroup_unlock();
 	return ret;
 }
 
@@ -5385,7 +5395,7 @@ static void css_release_work_fn(struct work_struct *work)
 	struct cgroup_subsys *ss = css->ss;
 	struct cgroup *cgrp = css->cgroup;
 
-	mutex_lock(&cgroup_mutex);
+	cgroup_lock();
 
 	css->flags |= CSS_RELEASED;
 	list_del_rcu(&css->sibling);
@@ -5426,7 +5436,7 @@ static void css_release_work_fn(struct work_struct *work)
 					 NULL);
 	}
 
-	mutex_unlock(&cgroup_mutex);
+	cgroup_unlock();
 
 	INIT_RCU_WORK(&css->destroy_rwork, css_free_rwork_fn);
 	queue_rcu_work(cgroup_destroy_wq, &css->destroy_rwork);
@@ -5774,7 +5784,7 @@ static void css_killed_work_fn(struct work_struct *work)
 	struct cgroup_subsys_state *css =
 		container_of(work, struct cgroup_subsys_state, destroy_work);
 
-	mutex_lock(&cgroup_mutex);
+	cgroup_lock();
 
 	do {
 		offline_css(css);
@@ -5783,7 +5793,7 @@ static void css_killed_work_fn(struct work_struct *work)
 		css = css->parent;
 	} while (css && atomic_dec_and_test(&css->online_cnt));
 
-	mutex_unlock(&cgroup_mutex);
+	cgroup_unlock();
 }
 
 /* css kill confirmation processing requires process context, bounce */
@@ -5967,7 +5977,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early)
 
 	pr_debug("Initializing cgroup subsys %s\n", ss->name);
 
-	mutex_lock(&cgroup_mutex);
+	cgroup_lock();
 
 	idr_init(&ss->css_idr);
 	INIT_LIST_HEAD(&ss->cfts);
@@ -6011,7 +6021,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early)
 
 	BUG_ON(online_css(css));
 
-	mutex_unlock(&cgroup_mutex);
+	cgroup_unlock();
 }
 
 /**
@@ -6071,7 +6081,7 @@ int __init cgroup_init(void)
 
 	get_user_ns(init_cgroup_ns.user_ns);
 
-	mutex_lock(&cgroup_mutex);
+	cgroup_lock();
 
 	/*
 	 * Add init_css_set to the hash table so that dfl_root can link to
@@ -6082,7 +6092,7 @@ int __init cgroup_init(void)
 
 	BUG_ON(cgroup_setup_root(&cgrp_dfl_root, 0));
 
-	mutex_unlock(&cgroup_mutex);
+	cgroup_unlock();
 
 	for_each_subsys(ss, ssid) {
 		if (ss->early_init) {
@@ -6134,9 +6144,9 @@ int __init cgroup_init(void)
 		if (ss->bind)
 			ss->bind(init_css_set.subsys[ssid]);
 
-		mutex_lock(&cgroup_mutex);
+		cgroup_lock();
 		css_populate_dir(init_css_set.subsys[ssid]);
-		mutex_unlock(&cgroup_mutex);
+		cgroup_unlock();
 	}
 
 	/* init_css_set.subsys[] has been updated, re-hash */
@@ -6241,7 +6251,7 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
 	if (!buf)
 		goto out;
 
-	mutex_lock(&cgroup_mutex);
+	cgroup_lock();
 	spin_lock_irq(&css_set_lock);
 
 	for_each_root(root) {
@@ -6296,7 +6306,7 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
 	retval = 0;
 out_unlock:
 	spin_unlock_irq(&css_set_lock);
-	mutex_unlock(&cgroup_mutex);
+	cgroup_unlock();
 	kfree(buf);
 out:
 	return retval;
@@ -6380,7 +6390,7 @@ static int cgroup_css_set_fork(struct kernel_clone_args *kargs)
 	struct file *f;
 
 	if (kargs->flags & CLONE_INTO_CGROUP)
-		mutex_lock(&cgroup_mutex);
+		cgroup_lock();
 
 	cgroup_threadgroup_change_begin(current);
 
@@ -6455,7 +6465,7 @@ static int cgroup_css_set_fork(struct kernel_clone_args *kargs)
 
 err:
 	cgroup_threadgroup_change_end(current);
-	mutex_unlock(&cgroup_mutex);
+	cgroup_unlock();
 	if (f)
 		fput(f);
 	if (dst_cgrp)
@@ -6482,7 +6492,7 @@ static void cgroup_css_set_put_fork(struct kernel_clone_args *kargs)
 		struct cgroup *cgrp = kargs->cgrp;
 		struct css_set *cset = kargs->cset;
 
-		mutex_unlock(&cgroup_mutex);
+		cgroup_unlock();
 
 		if (cset) {
 			put_css_set(cset);
@@ -6856,14 +6866,12 @@ EXPORT_SYMBOL_GPL(cgroup_get_from_path);
 struct cgroup *cgroup_v1v2_get_from_fd(int fd)
 {
 	struct cgroup *cgrp;
-	struct file *f;
-
-	f = fget_raw(fd);
-	if (!f)
+	struct fd f = fdget_raw(fd);
+	if (!f.file)
 		return ERR_PTR(-EBADF);
 
-	cgrp = cgroup_v1v2_get_from_file(f);
-	fput(f);
+	cgrp = cgroup_v1v2_get_from_file(f.file);
+	fdput(f);
 	return cgrp;
 }