Patch "ARM: function_graph: Simplify with function_graph_enter()" has been added to the 4.9-stable tree

Patch "ARM: function_graph: Simplify with function_graph_enter()" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ARM: function_graph: Simplify with function_graph_enter()

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     arm-function_graph-simplify-with-function_graph_enter.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From f1f5b14afd7cce39e6a9b25c685e1ea34c231096 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Date: Sun, 18 Nov 2018 17:19:26 -0500
Subject: ARM: function_graph: Simplify with function_graph_enter()

From: Steven Rostedt (VMware) <rostedt@goodmis.org>

commit f1f5b14afd7cce39e6a9b25c685e1ea34c231096 upstream.

The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().

Have ARM use the new code, and remove the shadow stack management as well as
having to set up the trace structure.

This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.

Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Cc: stable@kernel.org
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/arm/kernel/ftrace.c |   17 +----------------
 1 file changed, 1 insertion(+), 16 deletions(-)

--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -199,9 +199,7 @@ void prepare_ftrace_return(unsigned long
 			   unsigned long frame_pointer)
 {
 	unsigned long return_hooker = (unsigned long) &return_to_handler;
-	struct ftrace_graph_ent trace;
 	unsigned long old;
-	int err;
 
 	if (unlikely(atomic_read(&current->tracing_graph_pause)))
 		return;
@@ -209,21 +207,8 @@ void prepare_ftrace_return(unsigned long
 	old = *parent;
 	*parent = return_hooker;
 
-	trace.func = self_addr;
-	trace.depth = current->curr_ret_stack + 1;
-
-	/* Only trace if the calling function expects to */
-	if (!ftrace_graph_entry(&trace)) {
+	if (function_graph_enter(old, self_addr, frame_pointer, NULL))
 		*parent = old;
-		return;
-	}
-
-	err = ftrace_push_return_trace(old, self_addr, &trace.depth,
-				       frame_pointer, NULL);
-	if (err == -EBUSY) {
-		*parent = old;
-		return;
-	}
 }
 
 #ifdef CONFIG_DYNAMIC_FTRACE


Patches currently in stable-queue which might be from rostedt@goodmis.org are

queue-4.9/function_graph-create-function_graph_enter-to-consolidate-architecture-code.patch
queue-4.9/sh-function_graph-simplify-with-function_graph_enter.patch
queue-4.9/function_graph-move-return-callback-before-update-of-curr_ret_stack.patch
queue-4.9/function_graph-use-new-curr_ret_depth-to-manage-depth-instead-of-curr_ret_stack.patch
queue-4.9/sparc-function_graph-simplify-with-function_graph_enter.patch
queue-4.9/parisc-function_graph-simplify-with-function_graph_enter.patch
queue-4.9/x86-function_graph-simplify-with-function_graph_enter.patch
queue-4.9/function_graph-reverse-the-order-of-pushing-the-ret_stack-and-the-callback.patch
queue-4.9/arm-function_graph-simplify-with-function_graph_enter.patch
queue-4.9/function_graph-make-ftrace_push_return_trace-static.patch
queue-4.9/arm64-function_graph-simplify-with-function_graph_enter.patch
queue-4.9/s390-function_graph-simplify-with-function_graph_enter.patch
queue-4.9/microblaze-function_graph-simplify-with-function_graph_enter.patch
queue-4.9/function_graph-have-profiler-use-curr_ret_stack-and-not-depth.patch

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