From 572f3d94fd4fb7ffb0f6918fc7f98548817f476d Mon Sep 17 00:00:00 2001
From: Gabriele Monaco <gmonaco@redhat.com>
Date: Thu, 23 Jul 2026 09:45:33 +0200
Subject: [PATCH] selftests/verification: Rearrange the wwnr_printk test

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.

Wait for reactions to be over when expected by polling dmesg for an
interval without any rv message.
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
faster and more stable.

Reviewed-by: Wen Yang <wen.yang@linux.dev>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20260723074534.43521-17-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
 .../verification/test.d/rv_wwnr_printk.tc     | 28 +++++++++++++++++--
 1 file changed, 25 insertions(+), 3 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 96de95edb530..17e1edfb3902 100644
--- a/tools/testing/selftests/verification/test.d/rv_wwnr_printk.tc
+++ b/tools/testing/selftests/verification/test.d/rv_wwnr_printk.tc
@@ -4,11 +4,29 @@
 # 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 "$load_pid" || true
+	wait "$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
@@ -17,12 +35,16 @@ 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