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: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Li Zefan · Linus Torvalds
1 parent c8163ca8af
Showing 1 changed file with 16 additions and 35 deletions Side-by-side Diff
kernel/cpuset.c
@@ -1015,18 +1015,13 @@
 	struct cpuset *cs;
 	int migrate;
 	const nodemask_t *oldmem = scan->data;
-	NODEMASK_ALLOC(nodemask_t, newmems, GFP_KERNEL);
+	static nodemask_t newmems;	/* protected by cgroup_mutex */
  
-	if (!newmems)
-		return;
-
 	cs = cgroup_cs(scan->cg);
-	guarantee_online_mems(cs, newmems);
+	guarantee_online_mems(cs, &newmems);
  
-	cpuset_change_task_nodemask(p, newmems);
+	cpuset_change_task_nodemask(p, &newmems);
  
-	NODEMASK_FREE(newmems);
-
 	mm = get_task_mm(p);
 	if (!mm)
 		return;
  
  
  
  
  
  
  
  
@@ -1438,41 +1433,35 @@
 	struct mm_struct *mm;
 	struct cpuset *cs = cgroup_cs(cont);
 	struct cpuset *oldcs = cgroup_cs(oldcont);
-	NODEMASK_ALLOC(nodemask_t, to, GFP_KERNEL);
+	static nodemask_t to;		/* protected by cgroup_mutex */
  
-	if (to == NULL)
-		goto alloc_fail;
-
 	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 */
  
@@ -2055,11 +2044,8 @@
 	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);
+	static nodemask_t oldmems;	/* protected by cgroup_mutex */
  
-	if (oldmems == NULL)
-		return;
-
 	list_add_tail((struct list_head *)&root->stack_list, &queue);
  
 	while (!list_empty(&queue)) {
@@ -2075,7 +2061,7 @@
 		    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 @@
 			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 @@
 static int cpuset_track_online_nodes(struct notifier_block *self,
 				unsigned long action, void *arg)
 {
-	NODEMASK_ALLOC(nodemask_t, oldmems, GFP_KERNEL);
+	static nodemask_t oldmems;	/* protected by cgroup_mutex */
  
-	if (oldmems == NULL)
-		return NOTIFY_DONE;
-
 	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 @@
 	}
 	cgroup_unlock();
  
-	NODEMASK_FREE(oldmems);
 	return NOTIFY_OK;
 }
 #endif
...	...	@@ -1015,18 +1015,13 @@
1015	1015	struct cpuset *cs;
1016	1016	int migrate;
1017	1017	const nodemask_t *oldmem = scan->data;
1018		- NODEMASK_ALLOC(nodemask_t, newmems, GFP_KERNEL);
	1018	+ static nodemask_t newmems; /* protected by cgroup_mutex */
1019	1019
1020		- if (!newmems)
1021		- return;
1022		-
1023	1020	cs = cgroup_cs(scan->cg);
1024		- guarantee_online_mems(cs, newmems);
	1021	+ guarantee_online_mems(cs, &newmems);
1025	1022
1026		- cpuset_change_task_nodemask(p, newmems);
	1023	+ cpuset_change_task_nodemask(p, &newmems);
1027	1024
1028		- NODEMASK_FREE(newmems);
1029		-
1030	1025	mm = get_task_mm(p);
1031	1026	if (!mm)
1032	1027	return;
1033	1028
1034	1029
1035	1030
1036	1031
1037	1032
1038	1033
1039	1034
1040	1035
...	...	@@ -1438,41 +1433,35 @@
1438	1433	struct mm_struct *mm;
1439	1434	struct cpuset *cs = cgroup_cs(cont);
1440	1435	struct cpuset *oldcs = cgroup_cs(oldcont);
1441		- NODEMASK_ALLOC(nodemask_t, to, GFP_KERNEL);
	1436	+ static nodemask_t to; /* protected by cgroup_mutex */
1442	1437
1443		- if (to == NULL)
1444		- goto alloc_fail;
1445		-
1446	1438	if (cs == &top_cpuset) {
1447	1439	cpumask_copy(cpus_attach, cpu_possible_mask);
1448	1440	} else {
1449	1441	guarantee_online_cpus(cs, cpus_attach);
1450	1442	}
1451		- guarantee_online_mems(cs, to);
	1443	+ guarantee_online_mems(cs, &to);
1452	1444
1453	1445	/* do per-task migration stuff possibly for each in the threadgroup */
1454		- cpuset_attach_task(tsk, to, cs);
	1446	+ cpuset_attach_task(tsk, &to, cs);
1455	1447	if (threadgroup) {
1456	1448	struct task_struct *c;
1457	1449	rcu_read_lock();
1458	1450	list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {
1459		- cpuset_attach_task(c, to, cs);
	1451	+ cpuset_attach_task(c, &to, cs);
1460	1452	}
1461	1453	rcu_read_unlock();
1462	1454	}
1463	1455
1464	1456	/* change mm; only needs to be done once even if threadgroup */
1465		- *to = cs->mems_allowed;
	1457	+ to = cs->mems_allowed;
1466	1458	mm = get_task_mm(tsk);
1467	1459	if (mm) {
1468		- mpol_rebind_mm(mm, to);
	1460	+ mpol_rebind_mm(mm, &to);
1469	1461	if (is_memory_migrate(cs))
1470		- cpuset_migrate_mm(mm, &oldcs->mems_allowed, to);
	1462	+ cpuset_migrate_mm(mm, &oldcs->mems_allowed, &to);
1471	1463	mmput(mm);
1472	1464	}
1473		-
1474		-alloc_fail:
1475		- NODEMASK_FREE(to);
1476	1465	}
1477	1466
1478	1467	/* The various types of files and directories in a cpuset file system */
1479	1468
...	...	@@ -2055,11 +2044,8 @@
2055	2044	struct cpuset cp; / scans cpusets being updated */
2056	2045	struct cpuset child; / scans child cpusets of cp */
2057	2046	struct cgroup *cont;
2058		- NODEMASK_ALLOC(nodemask_t, oldmems, GFP_KERNEL);
	2047	+ static nodemask_t oldmems; /* protected by cgroup_mutex */
2059	2048
2060		- if (oldmems == NULL)
2061		- return;
2062		-
2063	2049	list_add_tail((struct list_head *)&root->stack_list, &queue);
2064	2050
2065	2051	while (!list_empty(&queue)) {
...	...	@@ -2075,7 +2061,7 @@
2075	2061	nodes_subset(cp->mems_allowed, node_states[N_HIGH_MEMORY]))
2076	2062	continue;
2077	2063
2078		- *oldmems = cp->mems_allowed;
	2064	+ oldmems = cp->mems_allowed;
2079	2065
2080	2066	/* Remove offline cpus and mems from this cpuset. */
2081	2067	mutex_lock(&callback_mutex);
2082	2068
...	...	@@ -2091,10 +2077,9 @@
2091	2077	remove_tasks_in_empty_cpuset(cp);
2092	2078	else {
2093	2079	update_tasks_cpumask(cp, NULL);
2094		- update_tasks_nodemask(cp, oldmems, NULL);
	2080	+ update_tasks_nodemask(cp, &oldmems, NULL);
2095	2081	}
2096	2082	}
2097		- NODEMASK_FREE(oldmems);
2098	2083	}
2099	2084
2100	2085	/*
2101	2086
2102	2087
2103	2088
...	...	@@ -2136,19 +2121,16 @@
2136	2121	static int cpuset_track_online_nodes(struct notifier_block *self,
2137	2122	unsigned long action, void *arg)
2138	2123	{
2139		- NODEMASK_ALLOC(nodemask_t, oldmems, GFP_KERNEL);
	2124	+ static nodemask_t oldmems; /* protected by cgroup_mutex */
2140	2125
2141		- if (oldmems == NULL)
2142		- return NOTIFY_DONE;
2143		-
2144	2126	cgroup_lock();
2145	2127	switch (action) {
2146	2128	case MEM_ONLINE:
2147		- *oldmems = top_cpuset.mems_allowed;
	2129	+ oldmems = top_cpuset.mems_allowed;
2148	2130	mutex_lock(&callback_mutex);
2149	2131	top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
2150	2132	mutex_unlock(&callback_mutex);
2151		- update_tasks_nodemask(&top_cpuset, oldmems, NULL);
	2133	+ update_tasks_nodemask(&top_cpuset, &oldmems, NULL);
2152	2134	break;
2153	2135	case MEM_OFFLINE:
2154	2136	/*
...	...	@@ -2162,7 +2144,6 @@
2162	2144	}
2163	2145	cgroup_unlock();
2164	2146
2165		- NODEMASK_FREE(oldmems);
2166	2147	return NOTIFY_OK;
2167	2148	}
2168	2149	#endif