From 7eea4fce0246fe3a15ad7f3bb8d0a56d1f9440e6 Mon Sep 17 00:00:00 2001
From: Jiaxing Wang <wangjiaxing@insigma.com.cn>
Date: Sun, 20 Apr 2014 23:10:43 +0800
Subject: [PATCH] tracing/stack_trace: Skip 4 instead of 3 when using
ftrace_ops_list_func
When using ftrace_ops_list_func, we should skip 4 instead of 3,
to avoid ftrace_call+0x5/0xb appearing in the stack trace:
Depth Size Location (110 entries)
----- ---- --------
0) 2956 0 update_curr+0xe/0x1e0
1) 2956 68 ftrace_call+0x5/0xb
2) 2888 92 enqueue_entity+0x53/0xe80
3) 2796 80 enqueue_task_fair+0x47/0x7e0
4) 2716 28 enqueue_task+0x45/0x70
5) 2688 12 activate_task+0x22/0x30
Add a function using_ftrace_ops_list_func() to test for this while keeping
ftrace_ops_list_func to remain static.
Link: http://lkml.kernel.org/p/1398006644-5935-2-git-send-email-wangjiaxing@insigma.com.cn
Signed-off-by: Jiaxing Wang <wangjiaxing@insigma.com.cn>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/ftrace.c | 5 +++++
kernel/trace/trace.h | 1 +
kernel/trace/trace_stack.c | 8 ++++++--
3 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 846888ea2ba4c..3cfeb66bda670 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -313,6 +313,11 @@ static void update_ftrace_function(void)
ftrace_trace_function = func;
}
+int using_ftrace_ops_list_func(void)
+{
+ return ftrace_trace_function == ftrace_ops_list_func;
+}
+
static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
{
ops->next = *list;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 5d2f07d6746c0..8624b50414660 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -830,6 +830,7 @@ void ftrace_destroy_function_files(struct trace_array *tr);
void ftrace_init_global_array_ops(struct trace_array *tr);
void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func);
void ftrace_reset_array_ops(struct trace_array *tr);
+int using_ftrace_ops_list_func(void);
#else
static inline int ftrace_trace_task(struct task_struct *task)
{
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 21b320e5d163c..5aa9a5b9b6e2b 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -85,8 +85,12 @@ check_stack(unsigned long ip, unsigned long *stack)
max_stack_size = this_size;
- max_stack_trace.nr_entries = 0;
- max_stack_trace.skip = 3;
+ max_stack_trace.nr_entries = 0;
+
+ if (using_ftrace_ops_list_func())
+ max_stack_trace.skip = 4;
+ else
+ max_stack_trace.skip = 3;
save_stack_trace(&max_stack_trace);
--
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