Merge branch 'for-4.4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup fixes from Tejun Heo:
 "More change than I'd have liked at this stage.  The pids controller
  and the changes made to cgroup core to support it introduced and
  revealed several important issues.

   - Assigning membership to a newly created task and migrating it can
     race leading to incorrect accounting.  Oleg fixed it by widening
     threadgroup synchronization.  It looks like we'll be able to merge
     it with a different percpu rwsem which is used in fork path making
     things simpler and cheaper.

   - The recent change to extend cgroup membership to zombies (so that
     pid accounting can extend till the pid is actually released) missed
     pinning the underlying data structures leading to use-after-free.
     Fixed.

   - v2 hierarchy was calling subsystem callbacks with the wrong target
     cgroup_subsys_state based on the incorrect assumption that they
     share the same target.  pids is the first controller affected by
     this.  Subsys callbacks updated so that they can deal with
     multi-target migrations"

* 'for-4.4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup_pids: don't account for the root cgroup
  cgroup: fix handling of multi-destination migration from subtree_control enabling
  cgroup_freezer: simplify propagation of CGROUP_FROZEN clearing in freezer_attach()
  cgroup: pids: kill pids_fork(), simplify pids_can_fork() and pids_cancel_fork()
  cgroup: pids: fix race between cgroup_post_fork() and cgroup_migrate()
  cgroup: make css_set pin its css's to avoid use-afer-free
  cgroup: fix cftype->file_offset handling
This commit is contained in:
Linus Torvalds 2015-12-08 13:35:52 -08:00
commit 5406812e59
13 changed files with 202 additions and 183 deletions

View file

@ -90,7 +90,6 @@ enum {
*/
struct cgroup_file {
/* do not access any fields from outside cgroup core */
struct list_head node; /* anchored at css->files */
struct kernfs_node *kn;
};
@ -134,9 +133,6 @@ struct cgroup_subsys_state {
*/
u64 serial_nr;
/* all cgroup_files associated with this css */
struct list_head files;
/* percpu_ref killing and RCU release */
struct rcu_head rcu_head;
struct work_struct destroy_work;
@ -426,12 +422,9 @@ struct cgroup_subsys {
void (*css_reset)(struct cgroup_subsys_state *css);
void (*css_e_css_changed)(struct cgroup_subsys_state *css);
int (*can_attach)(struct cgroup_subsys_state *css,
struct cgroup_taskset *tset);
void (*cancel_attach)(struct cgroup_subsys_state *css,
struct cgroup_taskset *tset);
void (*attach)(struct cgroup_subsys_state *css,
struct cgroup_taskset *tset);
int (*can_attach)(struct cgroup_taskset *tset);
void (*cancel_attach)(struct cgroup_taskset *tset);
void (*attach)(struct cgroup_taskset *tset);
int (*can_fork)(struct task_struct *task, void **priv_p);
void (*cancel_fork)(struct task_struct *task, void *priv);
void (*fork)(struct task_struct *task, void *priv);

View file

@ -88,6 +88,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
int cgroup_rm_cftypes(struct cftype *cfts);
void cgroup_file_notify(struct cgroup_file *cfile);
char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry);
@ -119,8 +120,10 @@ struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state
struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos,
struct cgroup_subsys_state *css);
struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset);
struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset);
struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset,
struct cgroup_subsys_state **dst_cssp);
struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset,
struct cgroup_subsys_state **dst_cssp);
void css_task_iter_start(struct cgroup_subsys_state *css,
struct css_task_iter *it);
@ -235,30 +238,39 @@ void css_task_iter_end(struct css_task_iter *it);
/**
* cgroup_taskset_for_each - iterate cgroup_taskset
* @task: the loop cursor
* @dst_css: the destination css
* @tset: taskset to iterate
*
* @tset may contain multiple tasks and they may belong to multiple
* processes. When there are multiple tasks in @tset, if a task of a
* process is in @tset, all tasks of the process are in @tset. Also, all
* are guaranteed to share the same source and destination csses.
* processes.
*
* On the v2 hierarchy, there may be tasks from multiple processes and they
* may not share the source or destination csses.
*
* On traditional hierarchies, when there are multiple tasks in @tset, if a
* task of a process is in @tset, all tasks of the process are in @tset.
* Also, all are guaranteed to share the same source and destination csses.
*
* Iteration is not in any specific order.
*/
#define cgroup_taskset_for_each(task, tset) \
for ((task) = cgroup_taskset_first((tset)); (task); \
(task) = cgroup_taskset_next((tset)))
#define cgroup_taskset_for_each(task, dst_css, tset) \
for ((task) = cgroup_taskset_first((tset), &(dst_css)); \
(task); \
(task) = cgroup_taskset_next((tset), &(dst_css)))
/**
* cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset
* @leader: the loop cursor
* @dst_css: the destination css
* @tset: takset to iterate
*
* Iterate threadgroup leaders of @tset. For single-task migrations, @tset
* may not contain any.
*/
#define cgroup_taskset_for_each_leader(leader, tset) \
for ((leader) = cgroup_taskset_first((tset)); (leader); \
(leader) = cgroup_taskset_next((tset))) \
#define cgroup_taskset_for_each_leader(leader, dst_css, tset) \
for ((leader) = cgroup_taskset_first((tset), &(dst_css)); \
(leader); \
(leader) = cgroup_taskset_next((tset), &(dst_css))) \
if ((leader) != (leader)->group_leader) \
; \
else
@ -516,19 +528,6 @@ static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
pr_cont_kernfs_path(cgrp->kn);
}
/**
* cgroup_file_notify - generate a file modified event for a cgroup_file
* @cfile: target cgroup_file
*
* @cfile must have been obtained by setting cftype->file_offset.
*/
static inline void cgroup_file_notify(struct cgroup_file *cfile)
{
/* might not have been created due to one of the CFTYPE selector flags */
if (cfile->kn)
kernfs_notify(cfile->kn);
}
#else /* !CONFIG_CGROUPS */
struct cgroup_subsys_state;