netprio_cgroup: fix wrong memory access when NETPRIO_CGROUP=m
When the netprio_cgroup module is not loaded, net_prio_subsys_id
is -1, and so sock_update_prioidx() accesses cgroup_subsys array
with negative index subsys[-1].
Make the code resembles cls_cgroup code, which is bug free.
Origionally-authored-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: "David S. Miller" <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/netprio_cgroup.h b/include/net/netprio_cgroup.h
index 7b2d431..d58fdec 100644
--- a/include/net/netprio_cgroup.h
+++ b/include/net/netprio_cgroup.h
@@ -37,19 +37,51 @@
extern void sock_update_netprioidx(struct sock *sk);
-static inline struct cgroup_netprio_state
- *task_netprio_state(struct task_struct *p)
+#if IS_BUILTIN(CONFIG_NETPRIO_CGROUP)
+
+static inline u32 task_netprioidx(struct task_struct *p)
{
-#if IS_ENABLED(CONFIG_NETPRIO_CGROUP)
- return container_of(task_subsys_state(p, net_prio_subsys_id),
- struct cgroup_netprio_state, css);
-#else
- return NULL;
-#endif
+ struct cgroup_netprio_state *state;
+ u32 idx;
+
+ rcu_read_lock();
+ state = container_of(task_subsys_state(p, net_prio_subsys_id),
+ struct cgroup_netprio_state, css);
+ idx = state->prioidx;
+ rcu_read_unlock();
+ return idx;
+}
+
+#elif IS_MODULE(CONFIG_NETPRIO_CGROUP)
+
+static inline u32 task_netprioidx(struct task_struct *p)
+{
+ struct cgroup_netprio_state *state;
+ int subsys_id;
+ u32 idx = 0;
+
+ rcu_read_lock();
+ subsys_id = rcu_dereference_index_check(net_prio_subsys_id,
+ rcu_read_lock_held());
+ if (subsys_id >= 0) {
+ state = container_of(task_subsys_state(p, subsys_id),
+ struct cgroup_netprio_state, css);
+ idx = state->prioidx;
+ }
+ rcu_read_unlock();
+ return idx;
}
#else
+static inline u32 task_netprioidx(struct task_struct *p)
+{
+ return 0;
+}
+
+#endif /* CONFIG_NETPRIO_CGROUP */
+
+#else
#define sock_update_netprioidx(sk)
#endif
