sh: ftrace: Add call to ftrace_graph_is_dead() in function graph code

ftrace_stop() is going away as it disables parts of function tracing
that affects users that should not be affected. But ftrace_graph_stop()
is built on ftrace_stop(). Here's another example of killing all of
function tracing because something went wrong with function graph
tracing.

Instead of disabling all users of function tracing on function graph
error, disable only function graph tracing. To do this, the arch code
must call ftrace_graph_is_dead() before it implements function graph.

Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c
index 3c74f53db6db93fca6e6399062fbbc16d457caa0..079d70e6d74b3122adb2f48bebd8056ac4262e4a 100644 (file)
--- a/arch/sh/kernel/ftrace.c
+++ b/arch/sh/kernel/ftrace.c
@@ -344,6 +344,9 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
        struct ftrace_graph_ent trace;
        unsigned long return_hooker = (unsigned long)&return_to_handler;
 
+       if (unlikely(ftrace_graph_is_dead()))
+               return;
+
        if (unlikely(atomic_read(&current->tracing_graph_pause)))
                return;