Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: create rcu_my_thread_group_empty() wrapper
memcg: css_id() must be called under rcu_read_lock()
cgroup: Check task_lock in task_subsys_state()
sched: Fix an RCU warning in print_task()
cgroup: Fix an RCU warning in alloc_css_id()
cgroup: Fix an RCU warning in cgroup_path()
KEYS: Fix an RCU warning in the reading of user keys
KEYS: Fix an RCU warning
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index b8ad1ea..8f78073 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -530,6 +530,7 @@
{
return rcu_dereference_check(task->cgroups->subsys[subsys_id],
rcu_read_lock_held() ||
+ lockdep_is_held(&task->alloc_lock) ||
cgroup_lock_is_held());
}
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 07db2fe..db266bb 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -190,6 +190,8 @@
#ifdef CONFIG_PROVE_RCU
+extern int rcu_my_thread_group_empty(void);
+
/**
* rcu_dereference_check - rcu_dereference with debug checking
* @p: The pointer to read, prior to dereferencing
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index e2769e1..3a53c77 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1646,7 +1646,9 @@
int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen)
{
char *start;
- struct dentry *dentry = rcu_dereference(cgrp->dentry);
+ struct dentry *dentry = rcu_dereference_check(cgrp->dentry,
+ rcu_read_lock_held() ||
+ cgroup_lock_is_held());
if (!dentry || cgrp == dummytop) {
/*
@@ -1662,13 +1664,17 @@
*--start = '\0';
for (;;) {
int len = dentry->d_name.len;
+
if ((start -= len) < buf)
return -ENAMETOOLONG;
- memcpy(start, cgrp->dentry->d_name.name, len);
+ memcpy(start, dentry->d_name.name, len);
cgrp = cgrp->parent;
if (!cgrp)
break;
- dentry = rcu_dereference(cgrp->dentry);
+
+ dentry = rcu_dereference_check(cgrp->dentry,
+ rcu_read_lock_held() ||
+ cgroup_lock_is_held());
if (!cgrp->parent)
continue;
if (--start < buf)
@@ -4555,13 +4561,13 @@
{
int subsys_id, i, depth = 0;
struct cgroup_subsys_state *parent_css, *child_css;
- struct css_id *child_id, *parent_id = NULL;
+ struct css_id *child_id, *parent_id;
subsys_id = ss->subsys_id;
parent_css = parent->subsys[subsys_id];
child_css = child->subsys[subsys_id];
- depth = css_depth(parent_css) + 1;
parent_id = parent_css->id;
+ depth = parent_id->depth;
child_id = get_new_cssid(ss, depth);
if (IS_ERR(child_id))
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index 03a7ea1..49d808e 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -122,3 +122,14 @@
rcu = container_of(head, struct rcu_synchronize, head);
complete(&rcu->completion);
}
+
+#ifdef CONFIG_PROVE_RCU
+/*
+ * wrapper function to avoid #include problems.
+ */
+int rcu_my_thread_group_empty(void)
+{
+ return thread_group_empty(current);
+}
+EXPORT_SYMBOL_GPL(rcu_my_thread_group_empty);
+#endif /* #ifdef CONFIG_PROVE_RCU */
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 9b49db1..19be00b 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -114,7 +114,9 @@
{
char path[64];
+ rcu_read_lock();
cgroup_path(task_group(p)->css.cgroup, path, sizeof(path));
+ rcu_read_unlock();
SEQ_printf(m, " %s", path);
}
#endif
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6c755de..0f711c2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -811,10 +811,12 @@
* enabled in "curr" and "curr" is a child of "mem" in *cgroup*
* hierarchy(even if use_hierarchy is disabled in "mem").
*/
+ rcu_read_lock();
if (mem->use_hierarchy)
ret = css_is_ancestor(&curr->css, &mem->css);
else
ret = (curr == mem);
+ rcu_read_unlock();
css_put(&curr->css);
return ret;
}
@@ -2312,7 +2314,9 @@
/* record memcg information */
if (do_swap_account && swapout && memcg) {
+ rcu_read_lock();
swap_cgroup_record(ent, css_id(&memcg->css));
+ rcu_read_unlock();
mem_cgroup_get(memcg);
}
if (swapout && memcg)
@@ -2369,8 +2373,10 @@
{
unsigned short old_id, new_id;
+ rcu_read_lock();
old_id = css_id(&from->css);
new_id = css_id(&to->css);
+ rcu_read_unlock();
if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
mem_cgroup_swap_statistics(from, false);
@@ -4038,11 +4044,16 @@
put_page(page);
}
/* throught */
- if (ent.val && do_swap_account && !ret &&
- css_id(&mc.from->css) == lookup_swap_cgroup(ent)) {
- ret = MC_TARGET_SWAP;
- if (target)
- target->ent = ent;
+ if (ent.val && do_swap_account && !ret) {
+ unsigned short id;
+ rcu_read_lock();
+ id = css_id(&mc.from->css);
+ rcu_read_unlock();
+ if (id == lookup_swap_cgroup(ent)) {
+ ret = MC_TARGET_SWAP;
+ if (target)
+ target->ent = ent;
+ }
}
return ret;
}