Commit ee24d379 authored by Li Zefan's avatar Li Zefan Committed by Linus Torvalds
Browse files

cpuset: fix unchecked calls to NODEMASK_ALLOC() 



Those functions that use NODEMASK_ALLOC() can't propagate errno
to users, but will fail silently.

Fix it by using a static nodemask_t variable for each function, and
those variables are protected by cgroup_mutex;

[akpm@linux-foundation.org: fix comment spelling, strengthen cgroup_lock comment]
Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c8163ca8

kernel/cpuset.c

+16 −35
Original line number Diff line number Diff line
@@ -1015,17 +1015,12 @@ static void cpuset_change_nodemask(struct task_struct *p, 
	struct cpuset *cs;

	int migrate;

	const nodemask_t *oldmem = scan->data;

	NODEMASK_ALLOC(nodemask_t, newmems, GFP_KERNEL);



	if (!newmems)

		return;

	static nodemask_t newmems;	/* protected by cgroup_mutex */



	cs = cgroup_cs(scan->cg);

	guarantee_online_mems(cs, newmems);

	guarantee_online_mems(cs, &newmems);



	cpuset_change_task_nodemask(p, newmems);



	NODEMASK_FREE(newmems);

	cpuset_change_task_nodemask(p, &newmems);



	mm = get_task_mm(p);

	if (!mm)
@@ -1438,41 +1433,35 @@ static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cont, 
	struct mm_struct *mm;

	struct cpuset *cs = cgroup_cs(cont);

	struct cpuset *oldcs = cgroup_cs(oldcont);

	NODEMASK_ALLOC(nodemask_t, to, GFP_KERNEL);



	if (to == NULL)

		goto alloc_fail;

	static nodemask_t to;		/* protected by cgroup_mutex */



	if (cs == &top_cpuset) {

		cpumask_copy(cpus_attach, cpu_possible_mask);

	} else {

		guarantee_online_cpus(cs, cpus_attach);

	}

	guarantee_online_mems(cs, to);

	guarantee_online_mems(cs, &to);



	/* do per-task migration stuff possibly for each in the threadgroup */

	cpuset_attach_task(tsk, to, cs);

	cpuset_attach_task(tsk, &to, cs);

	if (threadgroup) {

		struct task_struct *c;

		rcu_read_lock();

		list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {

			cpuset_attach_task(c, to, cs);

			cpuset_attach_task(c, &to, cs);

		}

		rcu_read_unlock();

	}



	/* change mm; only needs to be done once even if threadgroup */

	*to = cs->mems_allowed;

	to = cs->mems_allowed;

	mm = get_task_mm(tsk);

	if (mm) {

		mpol_rebind_mm(mm, to);

		mpol_rebind_mm(mm, &to);

		if (is_memory_migrate(cs))

			cpuset_migrate_mm(mm, &oldcs->mems_allowed, to);

			cpuset_migrate_mm(mm, &oldcs->mems_allowed, &to);

		mmput(mm);

	}



alloc_fail:

	NODEMASK_FREE(to);

}



/* The various types of files and directories in a cpuset file system */
@@ -2055,10 +2044,7 @@ static void scan_for_empty_cpusets(struct cpuset *root) 
	struct cpuset *cp;	/* scans cpusets being updated */

	struct cpuset *child;	/* scans child cpusets of cp */

	struct cgroup *cont;

	NODEMASK_ALLOC(nodemask_t, oldmems, GFP_KERNEL);



	if (oldmems == NULL)

		return;

	static nodemask_t oldmems;	/* protected by cgroup_mutex */



	list_add_tail((struct list_head *)&root->stack_list, &queue);
@@ -2075,7 +2061,7 @@ static void scan_for_empty_cpusets(struct cpuset *root) 
		    nodes_subset(cp->mems_allowed, node_states[N_HIGH_MEMORY]))

			continue;



		*oldmems = cp->mems_allowed;

		oldmems = cp->mems_allowed;



		/* Remove offline cpus and mems from this cpuset. */

		mutex_lock(&callback_mutex);
@@ -2091,10 +2077,9 @@ static void scan_for_empty_cpusets(struct cpuset *root) 
			remove_tasks_in_empty_cpuset(cp);

		else {

			update_tasks_cpumask(cp, NULL);

			update_tasks_nodemask(cp, oldmems, NULL);

			update_tasks_nodemask(cp, &oldmems, NULL);

		}

	}

	NODEMASK_FREE(oldmems);

}



/*
@@ -2136,19 +2121,16 @@ void cpuset_update_active_cpus(void) 
static int cpuset_track_online_nodes(struct notifier_block *self,

				unsigned long action, void *arg)

{

	NODEMASK_ALLOC(nodemask_t, oldmems, GFP_KERNEL);



	if (oldmems == NULL)

		return NOTIFY_DONE;

	static nodemask_t oldmems;	/* protected by cgroup_mutex */



	cgroup_lock();

	switch (action) {

	case MEM_ONLINE:

		*oldmems = top_cpuset.mems_allowed;

		oldmems = top_cpuset.mems_allowed;

		mutex_lock(&callback_mutex);

		top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];

		mutex_unlock(&callback_mutex);

		update_tasks_nodemask(&top_cpuset, oldmems, NULL);

		update_tasks_nodemask(&top_cpuset, &oldmems, NULL);

		break;

	case MEM_OFFLINE:

		/*
@@ -2162,7 +2144,6 @@ static int cpuset_track_online_nodes(struct notifier_block *self, 
	}

	cgroup_unlock();



	NODEMASK_FREE(oldmems);

	return NOTIFY_OK;

}

#endif

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