Re: [RFA][PATCH 09/27] powerpc/ftrace: Add call to ftrace_graph_is_dead() in function graph code

[Steven Rostedt]

Ben,

Can you ack this please?

Thanks,

-- Steve


On Thu, 26 Jun 2014 12:52:30 -0400
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>
> 
> 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: Anton Blanchard <anton@xxxxxxxxx>
> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
> ---
>  arch/powerpc/kernel/ftrace.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
> index f202d0731b06..f8c0ce5523a5 100644
> --- a/arch/powerpc/kernel/ftrace.c
> +++ b/arch/powerpc/kernel/ftrace.c
> @@ -527,6 +527,9 @@ 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;
>  

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/