Commit 1e096209 authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'for-3.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup fixes from Tejun Heo:
 "This contains two fix patches for device_cgroup.  One fixes a
  regression introduced earlier in 3.7 cycle where device_cgroup could
  try to dereference the NULL parent of the root cgroup.  The other one
  is RCU usage fix."

* 'for-3.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  device_cgroup: fix RCU usage
  device_cgroup: fix unchecked cgroup parent usage
parents 9924a199 201e72ac
......@@ -164,8 +164,8 @@ static void dev_exception_clean(struct dev_cgroup *dev_cgroup)
struct dev_exception_item *ex, *tmp;
list_for_each_entry_safe(ex, tmp, &dev_cgroup->exceptions, list) {
list_del(&ex->list);
kfree(ex);
list_del_rcu(&ex->list);
kfree_rcu(ex, rcu);
}
}
......@@ -298,7 +298,7 @@ static int may_access(struct dev_cgroup *dev_cgroup,
struct dev_exception_item *ex;
bool match = false;
list_for_each_entry(ex, &dev_cgroup->exceptions, list) {
list_for_each_entry_rcu(ex, &dev_cgroup->exceptions, list) {
if ((refex->type & DEV_BLOCK) && !(ex->type & DEV_BLOCK))
continue;
if ((refex->type & DEV_CHAR) && !(ex->type & DEV_CHAR))
......@@ -352,6 +352,8 @@ static int parent_has_perm(struct dev_cgroup *childcg,
*/
static inline int may_allow_all(struct dev_cgroup *parent)
{
if (!parent)
return 1;
return parent->behavior == DEVCG_DEFAULT_ALLOW;
}
......@@ -376,11 +378,14 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
int count, rc;
struct dev_exception_item ex;
struct cgroup *p = devcgroup->css.cgroup;
struct dev_cgroup *parent = cgroup_to_devcgroup(p->parent);
struct dev_cgroup *parent = NULL;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (p->parent)
parent = cgroup_to_devcgroup(p->parent);
memset(&ex, 0, sizeof(ex));
b = buffer;
......@@ -391,11 +396,14 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup,
if (!may_allow_all(parent))
return -EPERM;
dev_exception_clean(devcgroup);
devcgroup->behavior = DEVCG_DEFAULT_ALLOW;
if (!parent)
break;
rc = dev_exceptions_copy(&devcgroup->exceptions,
&parent->exceptions);
if (rc)
return rc;
devcgroup->behavior = DEVCG_DEFAULT_ALLOW;
break;
case DEVCG_DENY:
dev_exception_clean(devcgroup);
......
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