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authorLinus Torvalds <torvalds@linux-foundation.org>2015-12-08 13:35:52 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-12-08 13:35:52 -0800
commit5406812e59761f6ba33ea0bf97e426666bdb0e28 (patch)
treee332877ab352be841ff709f307c6d70788771044 /include
parent633bb7388bf399b2d4b16951404d69f34f9ddbec (diff)
parent0b98f0c04245877ae0b625a7f0aa55b8ff98e0c4 (diff)
downloadleg-kernel-5406812e59761f6ba33ea0bf97e426666bdb0e28.tar.gz
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
Diffstat (limited to 'include')
-rw-r--r--include/linux/cgroup-defs.h13
-rw-r--r--include/linux/cgroup.h47
2 files changed, 26 insertions, 34 deletions
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 60d44b26276d..06b77f9dd3f2 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -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);
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 22e3754f89c5..cb91b44f5f78 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -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;