[PATCH PATCH 2/2] selftests: livepatch: test if ftrace can trace a livepatched function

From: Filipe Xavier
Date: Thu Mar 06 2025 - 16:52:35 EST


This new test makes sure that ftrace can trace a
function that was introduced by a livepatch.

Signed-off-by: Filipe Xavier <felipeaggger@xxxxxxxxx>
---
tools/testing/selftests/livepatch/test-ftrace.sh | 35 ++++++++++++++++++++++++
1 file changed, 35 insertions(+)

diff --git a/tools/testing/selftests/livepatch/test-ftrace.sh b/tools/testing/selftests/livepatch/test-ftrace.sh
index fe14f248913acbec46fb6c0fec38a2fc84209d39..35774c42e239b466599052d6a9cc3cf75b78d63d 100755
--- a/tools/testing/selftests/livepatch/test-ftrace.sh
+++ b/tools/testing/selftests/livepatch/test-ftrace.sh
@@ -61,4 +61,39 @@ livepatch: '$MOD_LIVEPATCH': unpatching complete
% rmmod $MOD_LIVEPATCH"


+# - verify livepatch can load
+# - check if traces have a patched function
+# - reset trace and unload livepatch
+
+start_test "trace livepatched function and check that the live patch remains in effect"
+
+FUNCTION_NAME="livepatch_cmdline_proc_show"
+
+load_lp $MOD_LIVEPATCH
+trace_function "$FUNCTION_NAME"
+
+if [[ "$(cat /proc/cmdline)" == "$MOD_LIVEPATCH: this has been live patched" ]] ; then
+ log "livepatch: ok"
+fi
+
+check_traced_function "$FUNCTION_NAME"
+
+cleanup_tracing
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+check_result "% insmod test_modules/$MOD_LIVEPATCH.ko
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+livepatch: '$MOD_LIVEPATCH': patching complete
+livepatch: ok
+% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
+livepatch: '$MOD_LIVEPATCH': starting unpatching transition
+livepatch: '$MOD_LIVEPATCH': completing unpatching transition
+livepatch: '$MOD_LIVEPATCH': unpatching complete
+% rmmod $MOD_LIVEPATCH"
+
exit 0

--
2.46.2