Commit 3425a200 authored by Naveen N Rao's avatar Naveen N Rao Committed by Shuah Khan
Browse files

selftests/ftrace: Add test to exercize function tracer across cpu hotplug 



Add a test to exercize cpu hotplug with the function tracer active to
ensure that sensitive functions in idle path are excluded from being
traced. This helps catch issues such as the one fixed by commit
4b3338aa ("powerpc/ftrace: Fix stack teardown in ftrace_no_trace").

Signed-off-by: default avatarNaveen N Rao <naveen@kernel.org>
Acked-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: default avatarShuah Khan <skhan@linuxfoundation.org>
parent 5bc9dc06

tools/testing/selftests/ftrace/test.d/ftrace/func_hotplug.tc

0 → 100644
+42 −0
Original line number Diff line number Diff line 
#!/bin/sh

# SPDX-License-Identifier: GPL-2.0-or-later

# description: ftrace - function trace across cpu hotplug

# requires: function:tracer



if ! which nproc ; then

  nproc() {

    ls -d /sys/devices/system/cpu/cpu[0-9]* | wc -l

  }

fi



NP=`nproc`



if [ $NP -eq 1 ] ;then

  echo "We cannot test cpu hotplug in UP environment"

  exit_unresolved

fi



# Find online cpu

for i in /sys/devices/system/cpu/cpu[1-9]*; do

	if [ -f $i/online ] && [ "$(cat $i/online)" = "1" ]; then

		cpu=$i

		break

	fi

done



if [ -z "$cpu" ]; then

	echo "We cannot test cpu hotplug with a single cpu online"

	exit_unresolved

fi



echo 0 > tracing_on

echo > trace



: "Set $(basename $cpu) offline/online with function tracer enabled"

echo function > current_tracer

echo 1 > tracing_on

(echo 0 > $cpu/online)

(echo "forked"; sleep 1)

(echo 1 > $cpu/online)

echo 0 > tracing_on

echo nop > current_tracer