[ 3.5.y.z extended stable ] Patch "ftrace: Consistently restore trace function on sysctl" has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Thu Apr 11 09:09:22 UTC 2013

This is a note to let you know that I have just added a patch titled

    ftrace: Consistently restore trace function on sysctl

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:


If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see



>From f206634a8d544b9724f850a99cca00118ef876d9 Mon Sep 17 00:00:00 2001
From: Jan Kiszka <jan.kiszka at siemens.com>
Date: Tue, 26 Mar 2013 17:53:03 +0100
Subject: [PATCH] ftrace: Consistently restore trace function on sysctl

commit 5000c418840b309251c5887f0b56503aae30f84c upstream.

If we reenable ftrace via syctl, we currently set ftrace_trace_function
based on the previous simplistic algorithm. This is inconsistent with
what update_ftrace_function does. So better call that helper instead.

Link: http://lkml.kernel.org/r/5151D26F.1070702@siemens.com

Signed-off-by: Jan Kiszka <jan.kiszka at siemens.com>
Signed-off-by: Steven Rostedt <rostedt at goodmis.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
 kernel/trace/ftrace.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 1b6ec54..00ea125 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4375,12 +4375,8 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,

 		/* we are starting ftrace again */
-		if (ftrace_ops_list != &ftrace_list_end) {
-			if (ftrace_ops_list->next == &ftrace_list_end)
-				ftrace_trace_function = ftrace_ops_list->func;
-			else
-				ftrace_trace_function = ftrace_ops_list_func;
-		}
+		if (ftrace_ops_list != &ftrace_list_end)
+			update_ftrace_function();

 	} else {
 		/* stopping ftrace calls (just send to ftrace_stub) */

More information about the kernel-team mailing list