tools/testing/selftests/verification/test.d/rv_wwnr_printk.tc

#!/bin/sh
# SPDX-License-Identifier: GPL-2.0-or-later
# description: Test wwnr monitor with printk reactor
# requires: available_reactors wwnr:monitor printk:reactor stress-ng:program

load() { # returns true if there was a reaction
	local lines_before num load_pid ret
	num=$((($(nproc) + 1) / 2))
	lines_before=$(dmesg | wc -l)
	stress-ng --cpu-sched "$num" --timer "$num" -t 5 -q &
	load_pid=$!
	timeout 5 dmesg -w | tail -n +$((lines_before + 1)) | \
		grep -m 1 -q "rv: monitor wwnr does not allow event"
	ret=$?
	kill "$load_pid" || true
	wait "$load_pid" || true
	return $ret
}

# loads may flood the ringbuffer, wait for all pending printks (timeout at 2 minutes)
wait_dmesg_flush() {
	local last_before last_after
	for _ in $(seq 400); do
		last_before=$last_after
		last_after=$(dmesg | grep "rv:" | tail -n 1 || true)
		[ "$last_before" = "$last_after" ] && return 0
		sleep .3
	done
	return 1
}

echo 1 > monitors/wwnr/enable
echo printk > monitors/wwnr/reactors

load

echo 0 > monitoring_on
wait_dmesg_flush

! load || false
echo 1 > monitoring_on

load

echo 0 > reacting_on
wait_dmesg_flush

! load || false
echo 1 > reacting_on

echo nop > monitors/wwnr/reactors
echo 0 > monitors/wwnr/enable