kprobe_ftrace.tc

#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
# description: Kprobe dynamic event with function tracer

[ -f kprobe_events ] || exit_unsupported # this is configurable
grep "function" available_tracers || exit_unsupported # this is configurable

# prepare
echo nop > current_tracer
echo _do_fork > set_ftrace_filter
echo 'p:testprobe _do_fork' > kprobe_events

# kprobe on / ftrace off
echo 1 > events/kprobes/testprobe/enable
echo > trace
( echo "forked")
grep testprobe trace
! grep '_do_fork <-' trace

# kprobe on / ftrace on
echo function > current_tracer
echo > trace
( echo "forked")
grep testprobe trace
grep '_do_fork <-' trace

# kprobe off / ftrace on
echo 0 > events/kprobes/testprobe/enable
echo > trace
( echo "forked")
! grep testprobe trace
grep '_do_fork <-' trace

# kprobe on / ftrace on
echo 1 > events/kprobes/testprobe/enable
echo function > current_tracer
echo > trace
( echo "forked")
grep testprobe trace
grep '_do_fork <-' trace

# kprobe on / ftrace off
echo nop > current_tracer
echo > trace
( echo "forked")
grep testprobe trace
! grep '_do_fork <-' trace