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-rwxr-xr-xtools/testing/selftests/lkdtm/stack-entropy.sh16
1 files changed, 15 insertions, 1 deletions
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