From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
A new file was added to the tracing directory that will allow a user to
place a PID into it and the task associated to that PID will not be traced
by the function tracer. If the function-fork option is enabled, then neither
will the children of that task be traced by the function tracer.
Cc: linux-kselftest@xxxxxxxxxxxxxxx
Cc: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
.../test.d/ftrace/func-filter-notrace-pid.tc | 108 ++++++++++++++++++
1 file changed, 108 insertions(+)
create mode 100644 tools/testing/selftests/ftrace/test.d/ftrace/func-filter-notrace-pid.tc
diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-notrace-pid.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-notrace-pid.tc
new file mode 100644
index 000000000000..8aa46a2ea133
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-notrace-pid.tc
@@ -0,0 +1,108 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: ftrace - function pid notrace filters
+# flags: instance
+
+# Make sure that function pid matching filter with notrace works.
+
+if ! grep -q function available_tracers; then
+ echo "no function tracer configured"
+ exit_unsupported
+fi
+
+if [ ! -f set_ftrace_notrace_pid ]; then
+ echo "set_ftrace_notrace_pid not found? Is function tracer not set?"
+ exit_unsupported
+fi
+
+if [ ! -f set_ftrace_filter ]; then
+ echo "set_ftrace_filter not found? Is function tracer not set?"
+ exit_unsupported
+fi
+
+do_function_fork=1
+
+if [ ! -f options/function-fork ]; then
+ do_function_fork=0
+ echo "no option for function-fork found. Option will not be tested."
+fi
+
+read PID _ < /proc/self/stat
+
+if [ $do_function_fork -eq 1 ]; then
+ # default value of function-fork option
+ orig_value=`grep function-fork trace_options`
+fi
+
+do_reset() {
+ if [ $do_function_fork -eq 0 ]; then
+ return
+ fi
+
+ echo > set_ftrace_notrace_pid
+ echo $orig_value > trace_options
+}
+
+fail() { # msg
+ do_reset
+ echo $1
+ exit_fail
+}
+
+do_test() {
+ disable_tracing
+
+ echo do_execve* > set_ftrace_filter
+ echo *do_fork >> set_ftrace_filter
+
+ echo $PID > set_ftrace_notrace_pid
+ echo function > current_tracer
+
+ if [ $do_function_fork -eq 1 ]; then
+ # don't allow children to be traced
+ echo nofunction-fork > trace_options
+ fi
+
+ enable_tracing
+ yield
+
+ count_pid=`cat trace | grep -v ^# | grep $PID | wc -l`
+ count_other=`cat trace | grep -v ^# | grep -v $PID | wc -l`
+
+ # count_pid should be 0
+ if [ $count_pid -ne 0 -o $count_other -eq 0 ]; then
+ fail "PID filtering not working? traced task = $count_pid; other tasks = $count_other "
+ fi
+
+ disable_tracing
+ clear_trace
+
+ if [ $do_function_fork -eq 0 ]; then
+ return
+ fi
+
+ # allow children to be traced
+ echo function-fork > trace_options
+
+ # With pid in both set_ftrace_pid and set_ftrace_notrace_pid
+ # there should not be any tasks traced.
+
+ echo $PID > set_ftrace_pid
+
+ enable_tracing
+ yield
+
+ count_pid=`cat trace | grep -v ^# | grep $PID | wc -l`
+ count_other=`cat trace | grep -v ^# | grep -v $PID | wc -l`
+
+ # both should be zero
+ if [ $count_pid -ne 0 -o $count_other -ne 0 ]; then
+ fail "PID filtering not following fork? traced task = $count_pid; other tasks = $count_other "
+ fi
+}
+
+do_test
+
+do_reset
+
+exit 0
--
2.25.1
