Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma

[linux.git] / kernel / trace / ftrace.c

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 53f6b6401cf05fe9d63be0b67d646d25eed929e7..02004ae918608f915b28341b6ed1b3b7f551c5a5 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -113,7 +113,7 @@ static int ftrace_disabled __read_mostly;
 
 static DEFINE_MUTEX(ftrace_lock);
 
-static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
+static struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
 static struct ftrace_ops global_ops;
 
@@ -169,8 +169,11 @@ int ftrace_nr_registered_ops(void)
 
        mutex_lock(&ftrace_lock);
 
-       for (ops = ftrace_ops_list;
-            ops != &ftrace_list_end; ops = ops->next)
+       for (ops = rcu_dereference_protected(ftrace_ops_list,
+                                            lockdep_is_held(&ftrace_lock));
+            ops != &ftrace_list_end;
+            ops = rcu_dereference_protected(ops->next,
+                                            lockdep_is_held(&ftrace_lock)))
                cnt++;
 
        mutex_unlock(&ftrace_lock);
@@ -275,10 +278,11 @@ static void update_ftrace_function(void)
         * If there's only one ftrace_ops registered, the ftrace_ops_list
         * will point to the ops we want.
         */
-       set_function_trace_op = ftrace_ops_list;
+       set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
+                                               lockdep_is_held(&ftrace_lock));
 
        /* If there's no ftrace_ops registered, just call the stub function */
-       if (ftrace_ops_list == &ftrace_list_end) {
+       if (set_function_trace_op == &ftrace_list_end) {
                func = ftrace_stub;
 
        /*
@@ -286,7 +290,8 @@ static void update_ftrace_function(void)
         * recursion safe and not dynamic and the arch supports passing ops,
         * then have the mcount trampoline call the function directly.
         */
-       } else if (ftrace_ops_list->next == &ftrace_list_end) {
+       } else if (rcu_dereference_protected(ftrace_ops_list->next,
+                       lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
                func = ftrace_ops_get_list_func(ftrace_ops_list);
 
        } else {
@@ -348,9 +353,11 @@ int using_ftrace_ops_list_func(void)
        return ftrace_trace_function == ftrace_ops_list_func;
 }
 
-static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
+static void add_ftrace_ops(struct ftrace_ops __rcu **list,
+                          struct ftrace_ops *ops)
 {
-       ops->next = *list;
+       rcu_assign_pointer(ops->next, *list);
+
        /*
         * We are entering ops into the list but another
         * CPU might be walking that list. We need to make sure
@@ -360,7 +367,8 @@ static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
        rcu_assign_pointer(*list, ops);
 }
 
-static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
+static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
+                            struct ftrace_ops *ops)
 {
        struct ftrace_ops **p;
 
@@ -368,7 +376,10 @@ static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
         * If we are removing the last function, then simply point
         * to the ftrace_stub.
         */
-       if (*list == ops && ops->next == &ftrace_list_end) {
+       if (rcu_dereference_protected(*list,
+                       lockdep_is_held(&ftrace_lock)) == ops &&
+           rcu_dereference_protected(ops->next,
+                       lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
                *list = &ftrace_list_end;
                return 0;
        }
@@ -1569,8 +1580,8 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
                return 0;
 #endif
 
-       hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash);
-       hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash);
+       rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
+       rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
 
        if (hash_contains_ip(ip, &hash))
                ret = 1;
@@ -2840,7 +2851,8 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
         * If there's no more ops registered with ftrace, run a
         * sanity check to make sure all rec flags are cleared.
         */
-       if (ftrace_ops_list == &ftrace_list_end) {
+       if (rcu_dereference_protected(ftrace_ops_list,
+                       lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
                struct ftrace_page *pg;
                struct dyn_ftrace *rec;
 
@@ -6453,7 +6465,8 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
        if (ftrace_enabled) {
 
                /* we are starting ftrace again */
-               if (ftrace_ops_list != &ftrace_list_end)
+               if (rcu_dereference_protected(ftrace_ops_list,
+                       lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
                        update_ftrace_function();
 
                ftrace_startup_sysctl();