diff options
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 71 |
1 files changed, 39 insertions, 32 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index e2f46ba37f72..0c753ddd223b 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -886,7 +886,9 @@ static void cgroup_diput(struct dentry *dentry, struct inode *inode) * per-subsystem and moved to css->id so that lookups are * successful until the target css is released. */ + mutex_lock(&cgroup_mutex); idr_remove(&cgrp->root->cgroup_idr, cgrp->id); + mutex_unlock(&cgroup_mutex); cgrp->id = -1; call_rcu(&cgrp->rcu_head, cgroup_free_rcu); @@ -1566,10 +1568,10 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, mutex_lock(&cgroup_mutex); mutex_lock(&cgroup_root_mutex); - root_cgrp->id = idr_alloc(&root->cgroup_idr, root_cgrp, - 0, 1, GFP_KERNEL); - if (root_cgrp->id < 0) + ret = idr_alloc(&root->cgroup_idr, root_cgrp, 0, 1, GFP_KERNEL); + if (ret < 0) goto unlock_drop; + root_cgrp->id = ret; /* Check for name clashes with existing mounts */ ret = -EBUSY; @@ -2763,10 +2765,7 @@ static int cgroup_cfts_commit(struct cftype *cfts, bool is_add) */ update_before = cgroup_serial_nr_next; - mutex_unlock(&cgroup_mutex); - /* add/rm files for all cgroups created before */ - rcu_read_lock(); css_for_each_descendant_pre(css, cgroup_css(root, ss)) { struct cgroup *cgrp = css->cgroup; @@ -2775,23 +2774,19 @@ static int cgroup_cfts_commit(struct cftype *cfts, bool is_add) inode = cgrp->dentry->d_inode; dget(cgrp->dentry); - rcu_read_unlock(); - dput(prev); prev = cgrp->dentry; + mutex_unlock(&cgroup_mutex); mutex_lock(&inode->i_mutex); mutex_lock(&cgroup_mutex); if (cgrp->serial_nr < update_before && !cgroup_is_dead(cgrp)) ret = cgroup_addrm_files(cgrp, cfts, is_add); - mutex_unlock(&cgroup_mutex); mutex_unlock(&inode->i_mutex); - - rcu_read_lock(); if (ret) break; } - rcu_read_unlock(); + mutex_unlock(&cgroup_mutex); dput(prev); deactivate_super(sb); return ret; @@ -2910,9 +2905,14 @@ static void cgroup_enable_task_cg_lists(void) * We should check if the process is exiting, otherwise * it will race with cgroup_exit() in that the list * 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(). */ + spin_lock_irq(&p->sighand->siglock); if (!(p->flags & PF_EXITING) && list_empty(&p->cg_list)) list_add(&p->cg_list, &task_css_set(p)->tasks); + spin_unlock_irq(&p->sighand->siglock); + task_unlock(p); } while_each_thread(g, p); read_unlock(&tasklist_lock); @@ -4112,17 +4112,17 @@ static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss) err = percpu_ref_init(&css->refcnt, css_release); if (err) - goto err_free; + goto err_free_css; init_css(css, ss, cgrp); err = cgroup_populate_dir(cgrp, 1 << ss->subsys_id); if (err) - goto err_free; + goto err_free_percpu_ref; err = online_css(css); if (err) - goto err_free; + goto err_clear_dir; dget(cgrp->dentry); css_get(css->parent); @@ -4138,8 +4138,11 @@ static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss) return 0; -err_free: +err_clear_dir: + cgroup_clear_dir(css->cgroup, 1 << css->ss->subsys_id); +err_free_percpu_ref: percpu_ref_cancel_init(&css->refcnt); +err_free_css: ss->css_free(css); return err; } @@ -4158,7 +4161,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, struct cgroup *cgrp; struct cgroup_name *name; struct cgroupfs_root *root = parent->root; - int ssid, err = 0; + int ssid, err; struct cgroup_subsys *ss; struct super_block *sb = root->sb; @@ -4168,19 +4171,13 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, return -ENOMEM; name = cgroup_alloc_name(dentry); - if (!name) + if (!name) { + err = -ENOMEM; goto err_free_cgrp; + } rcu_assign_pointer(cgrp->name, name); /* - * Temporarily set the pointer to NULL, so idr_find() won't return - * a half-baked cgroup. - */ - cgrp->id = idr_alloc(&root->cgroup_idr, NULL, 1, 0, GFP_KERNEL); - if (cgrp->id < 0) - goto err_free_name; - - /* * Only live parents can have children. Note that the liveliness * check isn't strictly necessary because cgroup_mkdir() and * cgroup_rmdir() are fully synchronized by i_mutex; however, do it @@ -4189,7 +4186,17 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, */ if (!cgroup_lock_live_group(parent)) { err = -ENODEV; - goto err_free_id; + goto err_free_name; + } + + /* + * Temporarily set the pointer to NULL, so idr_find() won't return + * a half-baked cgroup. + */ + cgrp->id = idr_alloc(&root->cgroup_idr, NULL, 1, 0, GFP_KERNEL); + if (cgrp->id < 0) { + err = -ENOMEM; + goto err_unlock; } /* Grab a reference on the superblock so the hierarchy doesn't @@ -4221,7 +4228,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, */ err = cgroup_create_file(dentry, S_IFDIR | mode, sb); if (err < 0) - goto err_unlock; + goto err_free_id; lockdep_assert_held(&dentry->d_inode->i_mutex); cgrp->serial_nr = cgroup_serial_nr_next++; @@ -4257,12 +4264,12 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, return 0; -err_unlock: - mutex_unlock(&cgroup_mutex); - /* Release the reference count that we took on the superblock */ - deactivate_super(sb); err_free_id: idr_remove(&root->cgroup_idr, cgrp->id); + /* Release the reference count that we took on the superblock */ + deactivate_super(sb); +err_unlock: + mutex_unlock(&cgroup_mutex); err_free_name: kfree(rcu_dereference_raw(cgrp->name)); err_free_cgrp: |
