From: "Steven Rostedt (VMware)" rostedt@goodmis.org

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@vger.kernel.org Cc: Shuah Khan skhan@linuxfoundation.org Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org --- .../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