1 files changed, 14 insertions, 4 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 6c508ff33c62..13f12351b350 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1416,12 +1416,22 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
  * the hashes are freed with call_rcu_sched().
  */
 static int
-ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
 {
         struct ftrace_hash *filter_hash;
         struct ftrace_hash *notrace_hash;
         int ret;
 
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+        /*
+         * There's a small race when adding ops that the ftrace handler
+         * that wants regs, may be called without them. We can not
+         * allow that handler to be called if regs is NULL.
+         */
+        if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
+                return 0;
+#endif
+
         filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
         notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
 
@@ -4188,7 +4198,7 @@ static inline void ftrace_startup_enable(int command) { }
 # define ftrace_shutdown_sysctl()       do { } while (0)
 
 static inline int
-ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
 {
         return 1;
 }
@@ -4211,7 +4221,7 @@ ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
         do_for_each_ftrace_op(op, ftrace_control_list) {
                 if (!(op->flags & FTRACE_OPS_FL_STUB) &&
                     !ftrace_function_local_disabled(op) &&
-                    ftrace_ops_test(op, ip))
+                    ftrace_ops_test(op, ip, regs))
                         op->func(ip, parent_ip, op, regs);
         } while_for_each_ftrace_op(op);
         trace_recursion_clear(TRACE_CONTROL_BIT);
@@ -4244,7 +4254,7 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
          */
         preempt_disable_notrace();
         do_for_each_ftrace_op(op, ftrace_ops_list) {
-                if (ftrace_ops_test(op, ip))
+                if (ftrace_ops_test(op, ip, regs))
                         op->func(ip, parent_ip, op, regs);
         } while_for_each_ftrace_op(op);
         preempt_enable_notrace();