On Tue, Mar 18, 2025 at 06:20:35PM -0300, Filipe Xavier wrote:
> Add new ftrace helpers functions cleanup_tracing, trace_function and
> check_traced_functions.
>
> Signed-off-by: Filipe Xavier <felipeagg...@gmail.com>
> ---
> tools/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
> 15601402dee6567837c2c49ba342eb357e410d18..dea9cc10a3f09662c57c2593cff49423302c8a5c
> 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() {
> @@ -352,3 +367,37 @@ 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 -q "$function" "$SYSFS_TRACING_DIR/trace" ; then
Small suggestion here: grep on "$function" may find partial string
matches, like:
$ echo 'hamburger' | grep 'ham'
hamburger
so it's probably safer to user --word-regexp to avoid longer function
names inadvertently matching:
$ echo 'hamburger' | grep -w 'ham'
$ echo 'ham' | grep -w 'ham'
ham
Also, maybe also --fixed-strings for the extra paranoid? Off the top of
my head, I don't think any C function characters are special regex (like
$ ^ [ ] etc.) so it's probably safe w/o.
-- Joe
