From: Steven Rostedt <rost...@goodmis.org>
The code was restructured where the function graph notrace code, that
would not trace a function and all its children is done by setting a
NOTRACE flag when the function that is not to be traced is hit.
There's a TRACE_GRAPH_NOTRACE_BIT which defines the bit in the flags and a
TRACE_GRAPH_NOTRACE which is the mask with that bit set. But the
restructuring used TRACE_GRAPH_NOTRACE_BIT when it should have used
TRACE_GRAPH_NOTRACE.
For example:
# cd /sys/kernel/tracing
# echo set_track_prepare stack_trace_save > set_graph_notrace
# echo function_graph > current_tracer
# cat trace
[..]
0) | __slab_free() {
0) | free_to_partial_list() {
0) | arch_stack_walk() {
0) | __unwind_start() {
0) 0.501 us | get_stack_info();
Where a non filter trace looks like:
# echo > set_graph_notrace
# cat trace
0) | free_to_partial_list() {
0) | set_track_prepare() {
0) | stack_trace_save() {
0) | arch_stack_walk() {
0) | __unwind_start() {
Where the filter should look like:
# cat trace
0) | free_to_partial_list() {
0) | _raw_spin_lock_irqsave() {
0) 0.350 us | preempt_count_add();
0) 0.351 us | do_raw_spin_lock();
0) 2.440 us | }
Fixes: b84214890a9bc ("function_graph: Move graph notrace bit to shadow stack
global var")
Signed-off-by: Steven Rostedt (Google) <rost...@goodmis.org>
---
kernel/trace/trace_functions_graph.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/trace_functions_graph.c
b/kernel/trace/trace_functions_graph.c
index 54d850997c0a..136c750b0b4d 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -198,7 +198,7 @@ int trace_graph_entry(struct ftrace_graph_ent *trace,
* returning from the function.
*/
if (ftrace_graph_notrace_addr(trace->func)) {
- *task_var |= TRACE_GRAPH_NOTRACE_BIT;
+ *task_var |= TRACE_GRAPH_NOTRACE;
/*
* Need to return 1 to have the return called
* that will clear the NOTRACE bit.
--
2.45.2
