| Message ID | 20250318-ftrace-sftest-livepatch-v2-1-60cb0aa95cca@gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | selftests: livepatch: test if ftrace can trace a livepatched function | expand |
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 <felipeaggger@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
On 3/24/25 3:36 PM, Joe Lawrence wrote: > On Tue, Mar 18, 2025 at 06:20:35PM -0300, Filipe Xavier wrote: >> [ ... snip ... ] >> >> + if [[ -n "$FTRACE_FILTER" ]]; then >> + echo "$FTRACE_FILTER" \ >> + | sed -e "/#### all functions enabled ####/d" >> + > "$SYSFS_TRACING_DIR/set_ftrace_filter" >> + fi > > Also, this may be more stylistic than a functional nit (I don't know for > sure), but shellcheck [1] seemed confused about these lines: > > In tools/testing/selftests/livepatch/functions.sh line 90: > > "$SYSFS_TRACING_DIR/set_ftrace_filter" > ^-- SC2188 (warning): This redirection doesn't have a command. Move to its command (or use 'true' as no-op). > > I wasn't going to comment on these until I saw shellcheck note them, but > I thought shell script convention was typically to end the line with the > redirection/pipe then escape the end of line like: > > commands | commands > \ > tee output.txt > > There are a few existing examples of this pattern if you grep the > functions.sh file for '\\$'. > > That said, I'm far from certain whether which order is better than the > other. The only reason for bringing it up is that shellcheck warns on > this patch's usage. > > [1] https://www.shellcheck.net/ > > -- Joe Thanks for review Joe, I'm sending a new version with all the fixes. Cheers Filipe
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 + die "Function ($function) did not appear in the trace" + fi + done + + cleanup_tracing +}
Add new ftrace helpers functions cleanup_tracing, trace_function and check_traced_functions. Signed-off-by: Filipe Xavier <felipeaggger@gmail.com> --- tools/testing/selftests/livepatch/functions.sh | 49 ++++++++++++++++++++++++++ 1 file changed, 49 insertions(+)