ftrace: Consistently restore trace function on sysctl enabling

commit 5000c418840b309251c5887f0b56503aae30f84c upstream.

If we reenable ftrace via syctl, we currently set ftrace_trace_function
based on the previous simplistic algorithm. This is inconsistent with
what update_ftrace_function does. So better call that helper instead.

Link: http://lkml.kernel.org/r/5151D26F.1070702@siemens.com
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 0943d2a..1b378d0 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3964,12 +3964,8 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
                ftrace_startup_sysctl();
 
                /* we are starting ftrace again */
-               if (ftrace_ops_list != &ftrace_list_end) {
-                       if (ftrace_ops_list->next == &ftrace_list_end)
-                               ftrace_trace_function = ftrace_ops_list->func;
-                       else
-                               ftrace_trace_function = ftrace_ops_list_func;
-               }
+               if (ftrace_ops_list != &ftrace_list_end)
+                       update_ftrace_function();
 
        } else {
                /* stopping ftrace calls (just send to ftrace_stub) */