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Subject[for-next][PATCH 12/12] tracing/function_graph: Fix filters for function_graph threshold
From: Joel Fernandes <agnel.joel@gmail.com>

Function graph tracer currently ignores filters if tracing_thresh is set.
For example, even if set_ftrace_pid is set, then its ignored if tracing_thresh
set, resulting in all processes being traced.

To fix this, we reuse the same entry function as when tracing_thresh is not
set and do everything as in the regular case except for writing the function entry
to the ring buffer.

Link: http://lkml.kernel.org/r/1466228694-2677-1-git-send-email-agnel.joel@gmail.com

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Joel Fernandes <agnel.joel@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_functions_graph.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 67cce7896aeb..7363ccf79512 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -338,6 +338,13 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
if (ftrace_graph_notrace_addr(trace->func))
return 1;

+ /*
+ * Stop here if tracing_threshold is set. We only write function return
+ * events to the ring buffer.
+ */
+ if (tracing_thresh)
+ return 1;
+
local_irq_save(flags);
cpu = raw_smp_processor_id();
data = per_cpu_ptr(tr->trace_buffer.data, cpu);
@@ -355,14 +362,6 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
return ret;
}

-static int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
-{
- if (tracing_thresh)
- return 1;
- else
- return trace_graph_entry(trace);
-}
-
static void
__trace_graph_function(struct trace_array *tr,
unsigned long ip, unsigned long flags, int pc)
@@ -457,7 +456,7 @@ static int graph_trace_init(struct trace_array *tr)
set_graph_array(tr);
if (tracing_thresh)
ret = register_ftrace_graph(&trace_graph_thresh_return,
- &trace_graph_thresh_entry);
+ &trace_graph_entry);
else
ret = register_ftrace_graph(&trace_graph_return,
&trace_graph_entry);
--
2.8.1

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