From 2ca7cd80207e458b06c11c2b0de8d975a48f51cc Mon Sep 17 00:00:00 2001 From: Filipe Xavier Date: Mon, 24 Mar 2025 19:50:18 -0300 Subject: [PATCH 1/2] selftests: livepatch: add new ftrace helpers functions Add new ftrace helpers functions cleanup_tracing, trace_function and check_traced_functions. Signed-off-by: Filipe Xavier Acked-by: Miroslav Benes Acked-by: Joe Lawrence Reviewed-by: Petr Mladek Tested-by: Petr Mladek Link: https://lore.kernel.org/r/20250324-ftrace-sftest-livepatch-v3-1-d9d7cc386c75@gmail.com Signed-off-by: Petr Mladek --- .../testing/selftests/livepatch/functions.sh | 49 +++++++++++++++++++ 1 file changed, 49 insertions(+) diff --git a/tools/testing/selftests/livepatch/functions.sh b/tools/testing/selftests/livepatch/functions.sh index e5d06fb402335..f5d1915bc95b6 100644 --- a/tools/testing/selftests/livepatch/functions.sh +++ b/tools/testing/selftests/livepatch/functions.sh @@ -10,6 +10,7 @@ SYSFS_KERNEL_DIR="/sys/kernel" SYSFS_KLP_DIR="$SYSFS_KERNEL_DIR/livepatch" SYSFS_DEBUG_DIR="$SYSFS_KERNEL_DIR/debug" SYSFS_KPROBES_DIR="$SYSFS_DEBUG_DIR/kprobes" +SYSFS_TRACING_DIR="$SYSFS_DEBUG_DIR/tracing" # Kselftest framework requirement - SKIP code is 4 ksft_skip=4 @@ -62,6 +63,9 @@ function push_config() { awk -F'[: ]' '{print "file " $1 " line " $2 " " $4}') FTRACE_ENABLED=$(sysctl --values kernel.ftrace_enabled) KPROBE_ENABLED=$(cat "$SYSFS_KPROBES_DIR/enabled") + TRACING_ON=$(cat "$SYSFS_TRACING_DIR/tracing_on") + CURRENT_TRACER=$(cat "$SYSFS_TRACING_DIR/current_tracer") + FTRACE_FILTER=$(cat "$SYSFS_TRACING_DIR/set_ftrace_filter") } function pop_config() { @@ -74,6 +78,17 @@ function pop_config() { if [[ -n "$KPROBE_ENABLED" ]]; then echo "$KPROBE_ENABLED" > "$SYSFS_KPROBES_DIR/enabled" fi + if [[ -n "$TRACING_ON" ]]; then + echo "$TRACING_ON" > "$SYSFS_TRACING_DIR/tracing_on" + fi + if [[ -n "$CURRENT_TRACER" ]]; then + echo "$CURRENT_TRACER" > "$SYSFS_TRACING_DIR/current_tracer" + fi + if [[ -n "$FTRACE_FILTER" ]]; then + echo "$FTRACE_FILTER" \ + | sed -e "/#### all functions enabled ####/d" \ + > "$SYSFS_TRACING_DIR/set_ftrace_filter" + fi } function set_dynamic_debug() { @@ -351,3 +366,37 @@ function check_sysfs_value() { die "Unexpected value in $path: $expected_value vs. $value" fi } + +# cleanup_tracing() - stop and clean up function tracing +function cleanup_tracing() { + echo 0 > "$SYSFS_TRACING_DIR/tracing_on" + echo "" > "$SYSFS_TRACING_DIR/set_ftrace_filter" + echo "nop" > "$SYSFS_TRACING_DIR/current_tracer" + echo "" > "$SYSFS_TRACING_DIR/trace" +} + +# trace_function(function) - start tracing of a function +# function - to be traced function +function trace_function() { + local function="$1"; shift + + cleanup_tracing + + echo "function" > "$SYSFS_TRACING_DIR/current_tracer" + echo "$function" > "$SYSFS_TRACING_DIR/set_ftrace_filter" + echo 1 > "$SYSFS_TRACING_DIR/tracing_on" +} + +# check_traced_functions(functions...) - check whether each function appeared in the trace log +# functions - list of functions to be checked +function check_traced_functions() { + local function + + for function in "$@"; do + if ! grep -Fwq "$function" "$SYSFS_TRACING_DIR/trace" ; then + die "Function ($function) did not appear in the trace" + fi + done + + cleanup_tracing +} From 474eecc882aefb53241af09ac54139bf6f700555 Mon Sep 17 00:00:00 2001 From: Filipe Xavier Date: Mon, 24 Mar 2025 19:50:19 -0300 Subject: [PATCH 2/2] selftests: livepatch: test if ftrace can trace a livepatched function This new test makes sure that ftrace can trace a function that was introduced by a livepatch. Signed-off-by: Filipe Xavier Acked-by: Miroslav Benes Acked-by: Joe Lawrence Reviewed-by: Petr Mladek Tested-by: Petr Mladek Link: https://lore.kernel.org/r/20250324-ftrace-sftest-livepatch-v3-2-d9d7cc386c75@gmail.com Signed-off-by: Petr Mladek --- .../selftests/livepatch/test-ftrace.sh | 34 +++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/tools/testing/selftests/livepatch/test-ftrace.sh b/tools/testing/selftests/livepatch/test-ftrace.sh index fe14f248913ac..094176f1a46ae 100755 --- a/tools/testing/selftests/livepatch/test-ftrace.sh +++ b/tools/testing/selftests/livepatch/test-ftrace.sh @@ -61,4 +61,38 @@ livepatch: '$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_functions "$FUNCTION_NAME" + +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 > $SYSFS_KLP_DIR/$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