Exit with return code 4 if lkdtm is not available like other tests in order to properly skip the test.

Signed-off-by: Misono Tomohiro misono.tomohiro@jp.fujitsu.com --- I saw the same problem reported here (on 5.14-rc4): https://lore.kernel.org/lkml/2836f48a-d4e2-7f00-f06c-9f556fbd6332@linuxfound...

tools/testing/selftests/lkdtm/stack-entropy.sh | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/lkdtm/stack-entropy.sh b/tools/testing/selftests/lkdtm/stack-entropy.sh index 1b4d95d575f8..14fedeef762e 100755 --- a/tools/testing/selftests/lkdtm/stack-entropy.sh +++ b/tools/testing/selftests/lkdtm/stack-entropy.sh @@ -4,13 +4,27 @@ # Measure kernel stack entropy by sampling via LKDTM's REPORT_STACK test. set -e samples="${1:-1000}" +TRIGGER=/sys/kernel/debug/provoke-crash/DIRECT +KSELFTEST_SKIP_TEST=4 + +# Verify we have LKDTM available in the kernel. +if [ ! -r $TRIGGER ] ; then + /sbin/modprobe -q lkdtm || true + if [ ! -r $TRIGGER ] ; then + echo "Cannot find $TRIGGER (missing CONFIG_LKDTM?)" + else + echo "Cannot write $TRIGGER (need to run as root?)" + fi + # Skip this test + exit $KSELFTEST_SKIP_TEST +fi

# Capture dmesg continuously since it may fill up depending on sample size. log=$(mktemp -t stack-entropy-XXXXXX) dmesg --follow >"$log" & pid=$! report=-1 for i in $(seq 1 $samples); do - echo "REPORT_STACK" >/sys/kernel/debug/provoke-crash/DIRECT + echo "REPORT_STACK" > $TRIGGER if [ -t 1 ]; then percent=$(( 100 * $i / $samples )) if [ "$percent" -ne "$report" ]; then