tracing/stack_trace: Skip 4 instead of 3 when using ftrace_ops_list_func (7eea4fce) · Commits · 戴 / test

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 −0

Original line number	Diff line number	Diff line
		@@ -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;

kernel/trace/trace.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -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)
		{

kernel/trace/trace_stack.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -86,6 +86,10 @@ check_stack(unsigned long ip, unsigned long *stack)
		max_stack_size = this_size;

		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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