1 files changed, 76 insertions, 72 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 86cb5c6e8932..75c0ff00aca6 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -837,6 +837,8 @@ static void put_css_set_locked(struct css_set *cset)
 
 static void put_css_set(struct css_set *cset)
 {
+        unsigned long flags;
+
         /*
          * Ensure that the refcount doesn't hit zero while any readers
          * can see it. Similar to atomic_dec_and_lock(), but for an
@@ -845,9 +847,9 @@ static void put_css_set(struct css_set *cset)
         if (atomic_add_unless(&cset->refcount, -1, 1))
                 return;
 
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irqsave(&css_set_lock, flags);
         put_css_set_locked(cset);
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irqrestore(&css_set_lock, flags);
 }
 
 /*
@@ -1070,11 +1072,11 @@ static struct css_set *find_css_set(struct css_set *old_cset,
 
         /* First see if we already have a cgroup group that matches
          * the desired set */
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         cset = find_existing_css_set(old_cset, cgrp, template);
         if (cset)
                 get_css_set(cset);
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 
         if (cset)
                 return cset;
@@ -1102,7 +1104,7 @@ static struct css_set *find_css_set(struct css_set *old_cset,
          * find_existing_css_set() */
         memcpy(cset->subsys, template, sizeof(cset->subsys));
 
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         /* Add reference counts and links from the new css_set. */
         list_for_each_entry(link, &old_cset->cgrp_links, cgrp_link) {
                 struct cgroup *c = link->cgrp;
@@ -1128,7 +1130,7 @@ static struct css_set *find_css_set(struct css_set *old_cset,
                 css_get(css);
         }
 
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 
         return cset;
 }
@@ -1192,7 +1194,7 @@ static void cgroup_destroy_root(struct cgroup_root *root)
          * Release all the links from cset_links to this hierarchy's
          * root cgroup
          */
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
 
         list_for_each_entry_safe(link, tmp_link, &cgrp->cset_links, cset_link) {
                 list_del(&link->cset_link);
@@ -1200,7 +1202,7 @@ static void cgroup_destroy_root(struct cgroup_root *root)
                 kfree(link);
         }
 
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 
         if (!list_empty(&root->root_list)) {
                 list_del(&root->root_list);
@@ -1600,11 +1602,11 @@ static int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask)
                 ss->root = dst_root;
                 css->cgroup = dcgrp;
 
-                spin_lock_bh(&css_set_lock);
+                spin_lock_irq(&css_set_lock);
                 hash_for_each(css_set_table, i, cset, hlist)
                         list_move_tail(&cset->e_cset_node[ss->id],
                                        &dcgrp->e_csets[ss->id]);
-                spin_unlock_bh(&css_set_lock);
+                spin_unlock_irq(&css_set_lock);
 
                 /* default hierarchy doesn't enable controllers by default */
                 dst_root->subsys_mask |= 1 << ssid;
@@ -1640,10 +1642,10 @@ static int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
         if (!buf)
                 return -ENOMEM;
 
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         ns_cgroup = current_cgns_cgroup_from_root(kf_cgroot);
         len = kernfs_path_from_node(kf_node, ns_cgroup->kn, buf, PATH_MAX);
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 
         if (len >= PATH_MAX)
                 len = -ERANGE;
@@ -1897,7 +1899,7 @@ static void cgroup_enable_task_cg_lists(void)
 {
         struct task_struct *p, *g;
 
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
 
         if (use_task_css_set_links)
                 goto out_unlock;
@@ -1922,8 +1924,12 @@ static void cgroup_enable_task_cg_lists(void)
                  * entry won't be deleted though the process has exited.
                  * Do it while holding siglock so that we don't end up
                  * racing against cgroup_exit().
+                 *
+                 * Interrupts were already disabled while acquiring
+                 * the css_set_lock, so we do not need to disable it
+                 * again when acquiring the sighand->siglock here.
                  */
-                spin_lock_irq(&p->sighand->siglock);
+                spin_lock(&p->sighand->siglock);
                 if (!(p->flags & PF_EXITING)) {
                         struct css_set *cset = task_css_set(p);
 
@@ -1932,11 +1938,11 @@ static void cgroup_enable_task_cg_lists(void)
                         list_add_tail(&p->cg_list, &cset->tasks);
                         get_css_set(cset);
                 }
-                spin_unlock_irq(&p->sighand->siglock);
+                spin_unlock(&p->sighand->siglock);
         } while_each_thread(g, p);
         read_unlock(&tasklist_lock);
 out_unlock:
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 }
 
 static void init_cgroup_housekeeping(struct cgroup *cgrp)
@@ -2043,13 +2049,13 @@ static int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
          * Link the root cgroup in this hierarchy into all the css_set
          * objects.
          */
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         hash_for_each(css_set_table, i, cset, hlist) {
                 link_css_set(&tmp_links, cset, root_cgrp);
                 if (css_set_populated(cset))
                         cgroup_update_populated(root_cgrp, true);
         }
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 
         BUG_ON(!list_empty(&root_cgrp->self.children));
         BUG_ON(atomic_read(&root->nr_cgrps) != 1);
@@ -2256,11 +2262,11 @@ out_mount:
                 struct cgroup *cgrp;
 
                 mutex_lock(&cgroup_mutex);
-                spin_lock_bh(&css_set_lock);
+                spin_lock_irq(&css_set_lock);
 
                 cgrp = cset_cgroup_from_root(ns->root_cset, root);
 
-                spin_unlock_bh(&css_set_lock);
+                spin_unlock_irq(&css_set_lock);
                 mutex_unlock(&cgroup_mutex);
 
                 nsdentry = kernfs_node_dentry(cgrp->kn, dentry->d_sb);
@@ -2337,11 +2343,11 @@ char *cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
         char *ret;
 
         mutex_lock(&cgroup_mutex);
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
 
         ret = cgroup_path_ns_locked(cgrp, buf, buflen, ns);
 
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
         mutex_unlock(&cgroup_mutex);
 
         return ret;
@@ -2369,7 +2375,7 @@ char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
         char *path = NULL;
 
         mutex_lock(&cgroup_mutex);
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
 
         root = idr_get_next(&cgroup_hierarchy_idr, &hierarchy_id);
 
@@ -2382,7 +2388,7 @@ char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
                         path = buf;
         }
 
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
         mutex_unlock(&cgroup_mutex);
         return path;
 }
@@ -2557,7 +2563,7 @@ static int cgroup_taskset_migrate(struct cgroup_taskset *tset,
          * the new cgroup.  There are no failure cases after here, so this
          * is the commit point.
          */
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         list_for_each_entry(cset, &tset->src_csets, mg_node) {
                 list_for_each_entry_safe(task, tmp_task, &cset->mg_tasks, cg_list) {
                         struct css_set *from_cset = task_css_set(task);
@@ -2568,7 +2574,7 @@ static int cgroup_taskset_migrate(struct cgroup_taskset *tset,
                         put_css_set_locked(from_cset);
                 }
         }
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 
         /*
          * Migration is committed, all target tasks are now on dst_csets.
@@ -2597,13 +2603,13 @@ out_cancel_attach:
                 }
         } while_each_subsys_mask();
 out_release_tset:
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         list_splice_init(&tset->dst_csets, &tset->src_csets);
         list_for_each_entry_safe(cset, tmp_cset, &tset->src_csets, mg_node) {
                 list_splice_tail_init(&cset->mg_tasks, &cset->tasks);
                 list_del_init(&cset->mg_node);
         }
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
         return ret;
 }
 
@@ -2634,7 +2640,7 @@ static void cgroup_migrate_finish(struct list_head *preloaded_csets)
 
         lockdep_assert_held(&cgroup_mutex);
 
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         list_for_each_entry_safe(cset, tmp_cset, preloaded_csets, mg_preload_node) {
                 cset->mg_src_cgrp = NULL;
                 cset->mg_dst_cgrp = NULL;
@@ -2642,7 +2648,7 @@ static void cgroup_migrate_finish(struct list_head *preloaded_csets)
                 list_del_init(&cset->mg_preload_node);
                 put_css_set_locked(cset);
         }
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 }
 
 /**
@@ -2783,7 +2789,7 @@ static int cgroup_migrate(struct task_struct *leader, bool threadgroup,
          * already PF_EXITING could be freed from underneath us unless we
          * take an rcu_read_lock.
          */
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         rcu_read_lock();
         task = leader;
         do {
@@ -2792,7 +2798,7 @@ static int cgroup_migrate(struct task_struct *leader, bool threadgroup,
                         break;
         } while_each_thread(leader, task);
         rcu_read_unlock();
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 
         return cgroup_taskset_migrate(&tset, root);
 }
@@ -2816,7 +2822,7 @@ static int cgroup_attach_task(struct cgroup *dst_cgrp,
                 return -EBUSY;
 
         /* look up all src csets */
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         rcu_read_lock();
         task = leader;
         do {
@@ -2826,7 +2832,7 @@ static int cgroup_attach_task(struct cgroup *dst_cgrp,
                         break;
         } while_each_thread(leader, task);
         rcu_read_unlock();
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 
         /* prepare dst csets and commit */
         ret = cgroup_migrate_prepare_dst(&preloaded_csets);
@@ -2859,9 +2865,9 @@ static int cgroup_procs_write_permission(struct task_struct *task,
                 struct cgroup *cgrp;
                 struct inode *inode;
 
-                spin_lock_bh(&css_set_lock);
+                spin_lock_irq(&css_set_lock);
                 cgrp = task_cgroup_from_root(task, &cgrp_dfl_root);
-                spin_unlock_bh(&css_set_lock);
+                spin_unlock_irq(&css_set_lock);
 
                 while (!cgroup_is_descendant(dst_cgrp, cgrp))
                         cgrp = cgroup_parent(cgrp);
@@ -2962,9 +2968,9 @@ int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk)
                 if (root == &cgrp_dfl_root)
                         continue;
 
-                spin_lock_bh(&css_set_lock);
+                spin_lock_irq(&css_set_lock);
                 from_cgrp = task_cgroup_from_root(from, root);
-                spin_unlock_bh(&css_set_lock);
+                spin_unlock_irq(&css_set_lock);
 
                 retval = cgroup_attach_task(from_cgrp, tsk, false);
                 if (retval)
@@ -3080,7 +3086,7 @@ static int cgroup_update_dfl_csses(struct cgroup *cgrp)
         percpu_down_write(&cgroup_threadgroup_rwsem);
 
         /* look up all csses currently attached to @cgrp's subtree */
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
                 struct cgrp_cset_link *link;
 
@@ -3088,14 +3094,14 @@ static int cgroup_update_dfl_csses(struct cgroup *cgrp)
                         cgroup_migrate_add_src(link->cset, dsct,
                                                &preloaded_csets);
         }
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 
         /* NULL dst indicates self on default hierarchy */
         ret = cgroup_migrate_prepare_dst(&preloaded_csets);
         if (ret)
                 goto out_finish;
 
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         list_for_each_entry(src_cset, &preloaded_csets, mg_preload_node) {
                 struct task_struct *task, *ntask;
 
@@ -3107,7 +3113,7 @@ static int cgroup_update_dfl_csses(struct cgroup *cgrp)
                 list_for_each_entry_safe(task, ntask, &src_cset->tasks, cg_list)
                         cgroup_taskset_add(task, &tset);
         }
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 
         ret = cgroup_taskset_migrate(&tset, cgrp->root);
 out_finish:
@@ -3908,10 +3914,10 @@ static int cgroup_task_count(const struct cgroup *cgrp)
         int count = 0;
         struct cgrp_cset_link *link;
 
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         list_for_each_entry(link, &cgrp->cset_links, cset_link)
                 count += atomic_read(&link->cset->refcount);
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
         return count;
 }
 
@@ -4249,7 +4255,7 @@ void css_task_iter_start(struct cgroup_subsys_state *css,
 
         memset(it, 0, sizeof(*it));
 
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
 
         it->ss = css->ss;
 
@@ -4262,7 +4268,7 @@ void css_task_iter_start(struct cgroup_subsys_state *css,
 
         css_task_iter_advance_css_set(it);
 
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 }
 
 /**
@@ -4280,7 +4286,7 @@ struct task_struct *css_task_iter_next(struct css_task_iter *it)
                 it->cur_task = NULL;
         }
 
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
 
         if (it->task_pos) {
                 it->cur_task = list_entry(it->task_pos, struct task_struct,
@@ -4289,7 +4295,7 @@ struct task_struct *css_task_iter_next(struct css_task_iter *it)
                 css_task_iter_advance(it);
         }
 
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 
         return it->cur_task;
 }
@@ -4303,10 +4309,10 @@ struct task_struct *css_task_iter_next(struct css_task_iter *it)
 void css_task_iter_end(struct css_task_iter *it)
 {
         if (it->cur_cset) {
-                spin_lock_bh(&css_set_lock);
+                spin_lock_irq(&css_set_lock);
                 list_del(&it->iters_node);
                 put_css_set_locked(it->cur_cset);
-                spin_unlock_bh(&css_set_lock);
+                spin_unlock_irq(&css_set_lock);
         }
 
         if (it->cur_task)
@@ -4338,10 +4344,10 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
         mutex_lock(&cgroup_mutex);
 
         /* all tasks in @from are being moved, all csets are source */
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         list_for_each_entry(link, &from->cset_links, cset_link)
                 cgroup_migrate_add_src(link->cset, to, &preloaded_csets);
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 
         ret = cgroup_migrate_prepare_dst(&preloaded_csets);
         if (ret)
@@ -5063,6 +5069,7 @@ static void init_and_link_css(struct cgroup_subsys_state *css,
         memset(css, 0, sizeof(*css));
         css->cgroup = cgrp;
         css->ss = ss;
+        css->id = -1;
         INIT_LIST_HEAD(&css->sibling);
         INIT_LIST_HEAD(&css->children);
         css->serial_nr = css_serial_nr_next++;
@@ -5150,7 +5157,7 @@ static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
 
         err = cgroup_idr_alloc(&ss->css_idr, NULL, 2, 0, GFP_KERNEL);
         if (err < 0)
-                goto err_free_percpu_ref;
+                goto err_free_css;
         css->id = err;
 
         /* @css is ready to be brought online now, make it visible */
@@ -5174,9 +5181,6 @@ static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
 
 err_list_del:
         list_del_rcu(&css->sibling);
-        cgroup_idr_remove(&ss->css_idr, css->id);
-err_free_percpu_ref:
-        percpu_ref_exit(&css->refcnt);
 err_free_css:
         call_rcu(&css->rcu_head, css_free_rcu_fn);
         return ERR_PTR(err);
@@ -5451,10 +5455,10 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
          */
         cgrp->self.flags &= ~CSS_ONLINE;
 
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         list_for_each_entry(link, &cgrp->cset_links, cset_link)
                 link->cset->dead = true;
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
 
         /* initiate massacre of all css's */
         for_each_css(css, ssid, cgrp)
@@ -5725,7 +5729,7 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
                 goto out;
 
         mutex_lock(&cgroup_mutex);
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
 
         for_each_root(root) {
                 struct cgroup_subsys *ss;
@@ -5778,7 +5782,7 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
 
         retval = 0;
 out_unlock:
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
         mutex_unlock(&cgroup_mutex);
         kfree(buf);
 out:
@@ -5923,13 +5927,13 @@ void cgroup_post_fork(struct task_struct *child)
         if (use_task_css_set_links) {
                 struct css_set *cset;
 
-                spin_lock_bh(&css_set_lock);
+                spin_lock_irq(&css_set_lock);
                 cset = task_css_set(current);
                 if (list_empty(&child->cg_list)) {
                         get_css_set(cset);
                         css_set_move_task(child, NULL, cset, false);
                 }
-                spin_unlock_bh(&css_set_lock);
+                spin_unlock_irq(&css_set_lock);
         }
 
         /*
@@ -5974,9 +5978,9 @@ void cgroup_exit(struct task_struct *tsk)
         cset = task_css_set(tsk);
 
         if (!list_empty(&tsk->cg_list)) {
-                spin_lock_bh(&css_set_lock);
+                spin_lock_irq(&css_set_lock);
                 css_set_move_task(tsk, cset, NULL, false);
-                spin_unlock_bh(&css_set_lock);
+                spin_unlock_irq(&css_set_lock);
         } else {
                 get_css_set(cset);
         }
@@ -6044,9 +6048,9 @@ static void cgroup_release_agent(struct work_struct *work)
         if (!pathbuf || !agentbuf)
                 goto out;
 
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         path = cgroup_path_ns_locked(cgrp, pathbuf, PATH_MAX, &init_cgroup_ns);
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
         if (!path)
                 goto out;
 
@@ -6306,12 +6310,12 @@ struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
                 return ERR_PTR(-EPERM);
 
         mutex_lock(&cgroup_mutex);
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
 
         cset = task_css_set(current);
         get_css_set(cset);
 
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
         mutex_unlock(&cgroup_mutex);
 
         new_ns = alloc_cgroup_ns();
@@ -6435,7 +6439,7 @@ static int current_css_set_cg_links_read(struct seq_file *seq, void *v)
         if (!name_buf)
                 return -ENOMEM;
 
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         rcu_read_lock();
         cset = rcu_dereference(current->cgroups);
         list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
@@ -6446,7 +6450,7 @@ static int current_css_set_cg_links_read(struct seq_file *seq, void *v)
                            c->root->hierarchy_id, name_buf);
         }
         rcu_read_unlock();
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
         kfree(name_buf);
         return 0;
 }
@@ -6457,7 +6461,7 @@ static int cgroup_css_links_read(struct seq_file *seq, void *v)
         struct cgroup_subsys_state *css = seq_css(seq);
         struct cgrp_cset_link *link;
 
-        spin_lock_bh(&css_set_lock);
+        spin_lock_irq(&css_set_lock);
         list_for_each_entry(link, &css->cgroup->cset_links, cset_link) {
                 struct css_set *cset = link->cset;
                 struct task_struct *task;
@@ -6480,7 +6484,7 @@ static int cgroup_css_links_read(struct seq_file *seq, void *v)
         overflow:
                 seq_puts(seq, "  ...\n");
         }
-        spin_unlock_bh(&css_set_lock);
+        spin_unlock_irq(&css_set_lock);
         return 0;
 }