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Commit 4b1c7840 authored by Tejun Heo's avatar Tejun Heo
Browse files

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: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarSerge E. Hallyn <serge.hallyn@ubuntu.com>
Cc: Aristeu Rozanski <aris@redhat.com>
Cc: Li Zefan <lizefan@huawei.com>
parent 5b805f2a

security/device_cgroup.c

+12 −0
Original line number Diff line number Diff line
@@ -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;