[PATCH v3 16/17] selftests/verification: Rearrange the wwnr_printk test

[Gabriele Monaco <gmonaco@redhat.com>]

The wwnr_printk test expects no reactions in some situations, after
fixing the bash assertion, the test is failing because expecting no
reaction after a previous step had reactions is flaky without making
sure all buffers are flushed.

Simplify the test and run the steps expecting no reaction before the one
expecting reactions. Also simplify the load function to stop loads as
soon as a reaction occurs, this limits the number of lines to flush and
makes tests overall more stable.

Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
 .../verification/test.d/rv_wwnr_printk.tc       | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/verification/test.d/rv_wwnr_printk.tc b/tools/testing/selftests/verification/test.d/rv_wwnr_printk.tc
index 96de95edb5..a23d22f6ec 100644
--- a/tools/testing/selftests/verification/test.d/rv_wwnr_printk.tc
+++ b/tools/testing/selftests/verification/test.d/rv_wwnr_printk.tc
@@ -4,27 +4,30 @@
 # requires: available_reactors wwnr:monitor printk:reactor stress-ng:program
 
 load() { # returns true if there was a reaction
-	local lines_before num
+	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
-	dmesg | tail -n $((lines_before + 1)) | grep -q "rv: monitor wwnr does not allow event"
+	stress-ng --cpu-sched "$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 "$load_pid"
+	wait "$load_pid"
+	return $ret
 }
 
 echo 1 > monitors/wwnr/enable
 echo printk > monitors/wwnr/reactors
 
-load
-
 echo 0 > monitoring_on
 ! load || false
 echo 1 > monitoring_on
 
-load
-
 echo 0 > reacting_on
 ! load || false
 echo 1 > reacting_on
 
+load
+
 echo nop > monitors/wwnr/reactors
 echo 0 > monitors/wwnr/enable
-- 
2.54.0