netprio_cgroup: fix wrong memory access when NETPRIO_CGROUP=m

[karo-tx-linux.git] / include / net / netprio_cgroup.h

diff --git a/include/net/netprio_cgroup.h b/include/net/netprio_cgroup.h
index 7b2d43139c8e750e4b49ce6bf2244f12858a3211..d58fdec47597bccc095a9da28066bd6b67acfc2f 100644 (file)
--- a/include/net/netprio_cgroup.h
+++ b/include/net/netprio_cgroup.h
@@ -37,19 +37,51 @@ extern int net_prio_subsys_id;
 
 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