[PATCH drivers/misc v2 3/4] selftests/lkdtm: Reset WARN_ONCE to avoid false negatives

From: Kees Cook
Date: Thu Jun 25 2020 - 16:37:11 EST


Since we expect to see warnings every time for many tests, just reset
the WARN_ONCE flags each time the script runs.

Fixes: 46d1a0f03d66 ("selftests/lkdtm: Add tests for LKDTM targets")
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
tools/testing/selftests/lkdtm/run.sh | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/tools/testing/selftests/lkdtm/run.sh b/tools/testing/selftests/lkdtm/run.sh
index ee64ff8df8f4..8383eb89d88a 100755
--- a/tools/testing/selftests/lkdtm/run.sh
+++ b/tools/testing/selftests/lkdtm/run.sh
@@ -8,6 +8,7 @@
#
set -e
TRIGGER=/sys/kernel/debug/provoke-crash/DIRECT
+CLEAR_ONCE=/sys/kernel/debug/clear_warn_once
KSELFTEST_SKIP_TEST=4

# Verify we have LKDTM available in the kernel.
@@ -67,6 +68,11 @@ cleanup() {
}
trap cleanup EXIT

+# Reset WARN_ONCE counters so we trip it each time this runs.
+if [ -w $CLEAR_ONCE ] ; then
+ echo 1 > $CLEAR_ONCE
+fi
+
# Save existing dmesg so we can detect new content below
dmesg > "$DMESG"

--
2.25.1