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device_cgroup: add lockdep asserts 

device_cgroup uses RCU safe ->exceptions list which is write-protected
by devcgroup_mutex and has had some issues using locking correctly.
Add lockdep asserts to utility functions so that future errors can be
easily detected.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Cc: Aristeu Rozanski <aris@redhat.com>
Cc: Li Zefan <lizefan@huawei.com>
This commit is contained in:
Tejun Heo 2012-11-06 09:16:53 -08:00
parent 5b805f2a76
commit 4b1c7840b7
1 changed files with 12 additions and 0 deletions
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12
security/device_cgroup.c
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@ -82,6 +82,8 @@ static int dev_exceptions_copy(struct list_head *dest, struct list_head *orig)
{
struct dev_exception_item *ex, *tmp, *new;
lockdep_assert_held(&devcgroup_mutex);
list_for_each_entry(ex, orig, list) {
new = kmemdup(ex, sizeof(*ex), GFP_KERNEL);
if (!new)
@ -107,6 +109,8 @@ static int dev_exception_add(struct dev_cgroup *dev_cgroup,
{
struct dev_exception_item *excopy, *walk;
lockdep_assert_held(&devcgroup_mutex);
excopy = kmemdup(ex, sizeof(*ex), GFP_KERNEL);
if (!excopy)
return -ENOMEM;
@ -137,6 +141,8 @@ static void dev_exception_rm(struct dev_cgroup *dev_cgroup,
{
struct dev_exception_item *walk, *tmp;
lockdep_assert_held(&devcgroup_mutex);
list_for_each_entry_safe(walk, tmp, &dev_cgroup->exceptions, list) {
if (walk->type != ex->type)
continue;
@ -163,6 +169,8 @@ static void dev_exception_clean(struct dev_cgroup *dev_cgroup)
{
struct dev_exception_item *ex, *tmp;
lockdep_assert_held(&devcgroup_mutex);
list_for_each_entry_safe(ex, tmp, &dev_cgroup->exceptions, list) {
list_del_rcu(&ex->list);
kfree_rcu(ex, rcu);
@ -298,6 +306,10 @@ static int may_access(struct dev_cgroup *dev_cgroup,
struct dev_exception_item *ex;
bool match = false;
rcu_lockdep_assert(rcu_read_lock_held() ||
lockdep_is_held(&devcgroup_mutex),
"device_cgroup::may_access() called without proper synchronization");
list_for_each_entry_rcu(ex, &dev_cgroup->exceptions, list) {
if ((refex->type & DEV_BLOCK) && !(ex->type & DEV_BLOCK))
continue;