Merge branch 'for-4.3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup (bcee19f4) · Commits · 戴 / test

include/linux/cgroup-defs.h

+2 −25

Original line number	Diff line number	Diff line
		@@ -473,31 +473,8 @@ struct cgroup_subsys {
		unsigned int depends_on;
		};

		extern struct percpu_rw_semaphore cgroup_threadgroup_rwsem;

		/**
		* cgroup_threadgroup_change_begin - threadgroup exclusion for cgroups
		* @tsk: target task
		*
		* Called from threadgroup_change_begin() and allows cgroup operations to
		* synchronize against threadgroup changes using a percpu_rw_semaphore.
		*/
		static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk)
		{
		percpu_down_read(&cgroup_threadgroup_rwsem);
		}

		/**
		* cgroup_threadgroup_change_end - threadgroup exclusion for cgroups
		* @tsk: target task
		*
		* Called from threadgroup_change_end(). Counterpart of
		* cgroup_threadcgroup_change_begin().
		*/
		static inline void cgroup_threadgroup_change_end(struct task_struct *tsk)
		{
		percpu_up_read(&cgroup_threadgroup_rwsem);
		}
		void cgroup_threadgroup_change_begin(struct task_struct *tsk);
		void cgroup_threadgroup_change_end(struct task_struct *tsk);

		#else /* CONFIG_CGROUPS */

include/linux/init_task.h

+8 −0

Original line number	Diff line number	Diff line
		@@ -25,6 +25,13 @@
		extern struct files_struct init_files;
		extern struct fs_struct init_fs;

		#ifdef CONFIG_CGROUPS
		#define INIT_GROUP_RWSEM(sig) \
		.group_rwsem = __RWSEM_INITIALIZER(sig.group_rwsem),
		#else
		#define INIT_GROUP_RWSEM(sig)
		#endif

		#ifdef CONFIG_CPUSETS
		#define INIT_CPUSET_SEQ(tsk) \
		.mems_allowed_seq = SEQCNT_ZERO(tsk.mems_allowed_seq),
		@@ -57,6 +64,7 @@ extern struct fs_struct init_fs;
		INIT_PREV_CPUTIME(sig) \
		.cred_guard_mutex = \
		__MUTEX_INITIALIZER(sig.cred_guard_mutex), \
		INIT_GROUP_RWSEM(sig) \
		}

		extern struct nsproxy init_nsproxy;

include/linux/sched.h

+12 −0

Original line number	Diff line number	Diff line
		@@ -762,6 +762,18 @@ struct signal_struct {
		unsigned audit_tty_log_passwd;
		struct tty_audit_buf *tty_audit_buf;
		#endif
		#ifdef CONFIG_CGROUPS
		/*
		* group_rwsem prevents new tasks from entering the threadgroup and
		* member tasks from exiting,a more specifically, setting of
		* PF_EXITING. fork and exit paths are protected with this rwsem
		* using threadgroup_change_begin/end(). Users which require
		* threadgroup to remain stable should use threadgroup_[un]lock()
		* which also takes care of exec path. Currently, cgroup is the
		* only user.
		*/
		struct rw_semaphore group_rwsem;
		#endif

		oom_flags_t oom_flags;
		short oom_score_adj; /* OOM kill score adjustment */

kernel/cgroup.c

+84 −26

Original line number	Diff line number	Diff line
		@@ -46,7 +46,6 @@
		#include <linux/slab.h>
		#include <linux/spinlock.h>
		#include <linux/rwsem.h>
		#include <linux/percpu-rwsem.h>
		#include <linux/string.h>
		#include <linux/sort.h>
		#include <linux/kmod.h>
		@@ -104,8 +103,6 @@ static DEFINE_SPINLOCK(cgroup_idr_lock);
		*/
		static DEFINE_SPINLOCK(release_agent_path_lock);

		struct percpu_rw_semaphore cgroup_threadgroup_rwsem;

		#define cgroup_assert_mutex_or_rcu_locked() \
		RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \
		!lockdep_is_held(&cgroup_mutex), \
		@@ -874,6 +871,48 @@ static struct css_set find_css_set(struct css_set old_cset,
		return cset;
		}

		void cgroup_threadgroup_change_begin(struct task_struct *tsk)
		{
		down_read(&tsk->signal->group_rwsem);
		}

		void cgroup_threadgroup_change_end(struct task_struct *tsk)
		{
		up_read(&tsk->signal->group_rwsem);
		}

		/**
		* threadgroup_lock - lock threadgroup
		* @tsk: member task of the threadgroup to lock
		*
		* Lock the threadgroup @tsk belongs to. No new task is allowed to enter
		* and member tasks aren't allowed to exit (as indicated by PF_EXITING) or
		* change ->group_leader/pid. This is useful for cases where the threadgroup
		* needs to stay stable across blockable operations.
		*
		* fork and exit explicitly call threadgroup_change_{begin\|end}() for
		* synchronization. While held, no new task will be added to threadgroup
		* and no existing live task will have its PF_EXITING set.
		*
		* de_thread() does threadgroup_change_{begin\|end}() when a non-leader
		* sub-thread becomes a new leader.
		*/
		static void threadgroup_lock(struct task_struct *tsk)
		{
		down_write(&tsk->signal->group_rwsem);
		}

		/**
		* threadgroup_unlock - unlock threadgroup
		* @tsk: member task of the threadgroup to unlock
		*
		* Reverse threadgroup_lock().
		*/
		static inline void threadgroup_unlock(struct task_struct *tsk)
		{
		up_write(&tsk->signal->group_rwsem);
		}

		static struct cgroup_root cgroup_root_from_kf(struct kernfs_root kf_root)
		{
		struct cgroup *root_cgrp = kf_root->kn->priv;
		@@ -2074,9 +2113,9 @@ static void cgroup_task_migrate(struct cgroup *old_cgrp,
		lockdep_assert_held(&css_set_rwsem);

		/*
		* We are synchronized through cgroup_threadgroup_rwsem against
		* PF_EXITING setting such that we can't race against cgroup_exit()
		* changing the css_set to init_css_set and dropping the old one.
		* We are synchronized through threadgroup_lock() against PF_EXITING
		* setting such that we can't race against cgroup_exit() changing the
		* css_set to init_css_set and dropping the old one.
		*/
		WARN_ON_ONCE(tsk->flags & PF_EXITING);
		old_cset = task_css_set(tsk);
		@@ -2133,11 +2172,10 @@ static void cgroup_migrate_finish(struct list_head *preloaded_csets)
		* @src_cset and add it to @preloaded_csets, which should later be cleaned
		* up by cgroup_migrate_finish().
		*
		* This function may be called without holding cgroup_threadgroup_rwsem
		* even if the target is a process. Threads may be created and destroyed
		* but as long as cgroup_mutex is not dropped, no new css_set can be put
		* into play and the preloaded css_sets are guaranteed to cover all
		* migrations.
		* This function may be called without holding threadgroup_lock even if the
		* target is a process. Threads may be created and destroyed but as long
		* as cgroup_mutex is not dropped, no new css_set can be put into play and
		* the preloaded css_sets are guaranteed to cover all migrations.
		*/
		static void cgroup_migrate_add_src(struct css_set *src_cset,
		struct cgroup *dst_cgrp,
		@@ -2240,7 +2278,7 @@ err:
		* @threadgroup: whether @leader points to the whole process or a single task
		*
		* Migrate a process or task denoted by @leader to @cgrp. If migrating a
		* process, the caller must be holding cgroup_threadgroup_rwsem. The
		* process, the caller must be holding threadgroup_lock of @leader. The
		* caller is also responsible for invoking cgroup_migrate_add_src() and
		* cgroup_migrate_prepare_dst() on the targets before invoking this
		* function and following up with cgroup_migrate_finish().
		@@ -2368,7 +2406,7 @@ out_release_tset:
		* @leader: the task or the leader of the threadgroup to be attached
		* @threadgroup: attach the whole threadgroup?
		*
		* Call holding cgroup_mutex and cgroup_threadgroup_rwsem.
		* Call holding cgroup_mutex and threadgroup_lock of @leader.
		*/
		static int cgroup_attach_task(struct cgroup *dst_cgrp,
		struct task_struct *leader, bool threadgroup)
		@@ -2460,13 +2498,14 @@ static ssize_t __cgroup_procs_write(struct kernfs_open_file of, char buf,
		if (!cgrp)
		return -ENODEV;

		percpu_down_write(&cgroup_threadgroup_rwsem);
		retry_find_task:
		rcu_read_lock();
		if (pid) {
		tsk = find_task_by_vpid(pid);
		if (!tsk) {
		rcu_read_unlock();
		ret = -ESRCH;
		goto out_unlock_rcu;
		goto out_unlock_cgroup;
		}
		} else {
		tsk = current;
		@@ -2482,23 +2521,37 @@ static ssize_t __cgroup_procs_write(struct kernfs_open_file of, char buf,
		*/
		if (tsk == kthreadd_task \|\| (tsk->flags & PF_NO_SETAFFINITY)) {
		ret = -EINVAL;
		goto out_unlock_rcu;
		rcu_read_unlock();
		goto out_unlock_cgroup;
		}

		get_task_struct(tsk);
		rcu_read_unlock();

		threadgroup_lock(tsk);
		if (threadgroup) {
		if (!thread_group_leader(tsk)) {
		/*
		* a race with de_thread from another thread's exec()
		* may strip us of our leadership, if this happens,
		* there is no choice but to throw this task away and
		* try again; this is
		* "double-double-toil-and-trouble-check locking".
		*/
		threadgroup_unlock(tsk);
		put_task_struct(tsk);
		goto retry_find_task;
		}
		}

		ret = cgroup_procs_write_permission(tsk, cgrp, of);
		if (!ret)
		ret = cgroup_attach_task(cgrp, tsk, threadgroup);

		put_task_struct(tsk);
		goto out_unlock_threadgroup;
		threadgroup_unlock(tsk);

		out_unlock_rcu:
		rcu_read_unlock();
		out_unlock_threadgroup:
		percpu_up_write(&cgroup_threadgroup_rwsem);
		put_task_struct(tsk);
		out_unlock_cgroup:
		cgroup_kn_unlock(of->kn);
		return ret ?: nbytes;
		}
		@@ -2643,8 +2696,6 @@ static int cgroup_update_dfl_csses(struct cgroup *cgrp)

		lockdep_assert_held(&cgroup_mutex);

		percpu_down_write(&cgroup_threadgroup_rwsem);

		/* look up all csses currently attached to @cgrp's subtree */
		down_read(&css_set_rwsem);
		css_for_each_descendant_pre(css, cgroup_css(cgrp, NULL)) {
		@@ -2700,8 +2751,17 @@ static int cgroup_update_dfl_csses(struct cgroup *cgrp)
		goto out_finish;
		last_task = task;

		threadgroup_lock(task);
		/* raced against de_thread() from another thread? */
		if (!thread_group_leader(task)) {
		threadgroup_unlock(task);
		put_task_struct(task);
		continue;
		}

		ret = cgroup_migrate(src_cset->dfl_cgrp, task, true);

		threadgroup_unlock(task);
		put_task_struct(task);

		if (WARN(ret, "cgroup: failed to update controllers for the default hierarchy (%d), further operations may crash or hang\n", ret))
		@@ -2711,7 +2771,6 @@ static int cgroup_update_dfl_csses(struct cgroup *cgrp)

		out_finish:
		cgroup_migrate_finish(&preloaded_csets);
		percpu_up_write(&cgroup_threadgroup_rwsem);
		return ret;
		}

		@@ -5024,7 +5083,6 @@ int __init cgroup_init(void)
		unsigned long key;
		int ssid, err;

		BUG_ON(percpu_init_rwsem(&cgroup_threadgroup_rwsem));
		BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
		BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));

kernel/fork.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -1149,6 +1149,10 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
		tty_audit_fork(sig);
		sched_autogroup_fork(sig);

		#ifdef CONFIG_CGROUPS
		init_rwsem(&sig->group_rwsem);
		#endif

		sig->oom_score_adj = current->signal->oom_score_adj;
		sig->oom_score_adj_min = current->signal->oom_score_adj_min;

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