Messages in this thread Patch in this message | | | Date | Sat, 19 Jul 2014 09:15:30 -0400 | From | Steven Rostedt <> | Subject | [for-next][PATCH 06/32] ftrace/x86: Add call to ftrace_graph_is_dead() in function graph code |
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From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
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.
Link: http://lkml.kernel.org/r/53C54D18.3020602@zytor.com
Acked-by: H. Peter Anvin <hpa@linux.intel.com> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- arch/x86/kernel/ftrace.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index cbc4a91b131e..3386dc9aa333 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -703,6 +703,9 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, unsigned long return_hooker = (unsigned long) &return_to_handler; + if (unlikely(ftrace_graph_is_dead())) + return; + if (unlikely(atomic_read(¤t->tracing_graph_pause))) return; -- 2.0.1
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