From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: [RFA][PATCH 09/27] powerpc/ftrace: Add call to ftrace_graph_is_dead() in function graph code Date: Thu, 26 Jun 2014 12:52:30 -0400 Message-ID: <20140626165850.107467021@goodmis.org> References: <20140626165221.736847419@goodmis.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.226]:30172 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757372AbaFZQ6w (ORCPT ); Thu, 26 Jun 2014 12:58:52 -0400 Content-Disposition: inline; filename=0009-powerpc-ftrace-Add-call-to-ftrace_graph_is_dead-in-f.patch Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Thomas Gleixner , Masami Hiramatsu , "H. Peter Anvin" , linux-arch@vger.kernel.org, "Rafael J. Wysocki" , Jiri Kosina , Josh Poimboeuf , Anton Blanchard , Benjamin Herrenschmidt From: "Steven Rostedt (Red Hat)" 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 Cc: Benjamin Herrenschmidt Signed-off-by: Steven Rostedt --- 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(¤t->tracing_graph_pause))) return; -- 2.0.0