This patchset add ftrace helpers functions and add a new test makes sure that ftrace can trace a function that was introduced by a livepatch.
Signed-off-by: Filipe Xavier felipeaggger@gmail.com --- Filipe Xavier (2): selftests: livepatch: add new ftrace helpers functions selftests: livepatch: test if ftrace can trace a livepatched function
tools/testing/selftests/livepatch/functions.sh | 45 ++++++++++++++++++++++++ tools/testing/selftests/livepatch/test-ftrace.sh | 35 ++++++++++++++++++ 2 files changed, 80 insertions(+) --- base-commit: 848e076317446f9c663771ddec142d7c2eb4cb43 change-id: 20250306-ftrace-sftest-livepatch-60d9dc472235
Best regards,
Add new ftrace helpers functions cleanup_tracing, trace_function and check_traced_function.
Signed-off-by: Filipe Xavier felipeaggger@gmail.com --- tools/testing/selftests/livepatch/functions.sh | 45 ++++++++++++++++++++++++++ 1 file changed, 45 insertions(+)
diff --git a/tools/testing/selftests/livepatch/functions.sh b/tools/testing/selftests/livepatch/functions.sh index 15601402dee6567837c2c49ba342eb357e410d18..512ab3a9c20cc5691bbf0863d837ffa0d40a15e9 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 +367,33 @@ 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_function(function) - check whether function appeared in trace log +# function - to be traced function +function check_traced_function() { + local function="$1"; shift + + if ! grep -q "$function" "$SYSFS_TRACING_DIR/trace" ; then + die "Function ($function) did not appear in the trace" + fi +}
This new test makes sure that ftrace can trace a function that was introduced by a livepatch.
Signed-off-by: Filipe Xavier felipeaggger@gmail.com --- 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
Hi,
+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"
trace_funtion() calls cleanup_ftrace() to prepare the test. Ok.
+if [[ "$(cat /proc/cmdline)" == "$MOD_LIVEPATCH: this has been live patched" ]] ; then
- log "livepatch: ok"
+fi
+check_traced_function "$FUNCTION_NAME"
+cleanup_tracing
Here, I suppose, cleanup_tracing() is called to clean up after the check above so that nothing stays and more tests can be added later. Right? Would it make sense then to call cleanup_tracing() in check_traced_function()? I think it would less error prone. If needed, check_traced_function() can always be upgraded so that it checks for more traced functions.
Miroslav
On 3/14/25 10:14 AM, Miroslav Benes wrote:
Hi,
+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"
trace_funtion() calls cleanup_ftrace() to prepare the test. Ok.
+if [[ "$(cat /proc/cmdline)" == "$MOD_LIVEPATCH: this has been live patched" ]] ; then
- log "livepatch: ok"
+fi
+check_traced_function "$FUNCTION_NAME"
+cleanup_tracing
Here, I suppose, cleanup_tracing() is called to clean up after the check above so that nothing stays and more tests can be added later. Right? Would it make sense then to call cleanup_tracing() in check_traced_function()? I think it would less error prone. If needed, check_traced_function() can always be upgraded so that it checks for more traced functions.
In cases where we need to check two or more functions with check_traced_function,
if there is cleanup_tracing, it will not be possible, make sense?
e.g: function1 call -> function2 call -> function3.
Miroslav
On Fri, 14 Mar 2025, Filipe Xavier wrote:
On 3/14/25 10:14 AM, Miroslav Benes wrote:
Hi,
+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"
trace_funtion() calls cleanup_ftrace() to prepare the test. Ok.
+if [[ "$(cat /proc/cmdline)" == "$MOD_LIVEPATCH: this has been live patched" ]] ; then
- log "livepatch: ok"
+fi
+check_traced_function "$FUNCTION_NAME"
+cleanup_tracing
Here, I suppose, cleanup_tracing() is called to clean up after the check above so that nothing stays and more tests can be added later. Right? Would it make sense then to call cleanup_tracing() in check_traced_function()? I think it would less error prone. If needed, check_traced_function() can always be upgraded so that it checks for more traced functions.
In cases where we need to check two or more functions with check_traced_function,
if there is cleanup_tracing, it will not be possible, make sense?
e.g: function1 call -> function2 call -> function3.
I meant... check_traced_function() (or check_traced_functions() in this case) can have multiple arguments. You would loop over them inside and then clean up. Or did I misunderstood?
Miroslav
On 3/17/25 6:07 AM, Miroslav Benes wrote:
On Fri, 14 Mar 2025, Filipe Xavier wrote:
On 3/14/25 10:14 AM, Miroslav Benes wrote:
Hi,
+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"
trace_funtion() calls cleanup_ftrace() to prepare the test. Ok.
+if [[ "$(cat /proc/cmdline)" == "$MOD_LIVEPATCH: this has been live patched" ]] ; then
- log "livepatch: ok"
+fi
+check_traced_function "$FUNCTION_NAME"
+cleanup_tracing
Here, I suppose, cleanup_tracing() is called to clean up after the check above so that nothing stays and more tests can be added later. Right? Would it make sense then to call cleanup_tracing() in check_traced_function()? I think it would less error prone. If needed, check_traced_function() can always be upgraded so that it checks for more traced functions.
In cases where we need to check two or more functions with check_traced_function,
if there is cleanup_tracing, it will not be possible, make sense?
e.g: function1 call -> function2 call -> function3.
I meant... check_traced_function() (or check_traced_functions() in this case) can have multiple arguments. You would loop over them inside and then clean up. Or did I misunderstood?
I hadn't thought of it that way, it makes perfect sense. I'll send a new version with this adjustment.
Miroslav
On Thu, 2025-03-06 at 18:51 -0300, Filipe Xavier wrote:
This patchset add ftrace helpers functions and add a new test makes sure that ftrace can trace a function that was introduced by a livepatch.
Signed-off-by: Filipe Xavier felipeaggger@gmail.com
Filipe Xavier (2): selftests: livepatch: add new ftrace helpers functions selftests: livepatch: test if ftrace can trace a livepatched function
tools/testing/selftests/livepatch/functions.sh | 45 ++++++++++++++++++++++++ tools/testing/selftests/livepatch/test-ftrace.sh | 35 ++++++++++++++++++ 2 files changed, 80 insertions(+)
Thanks for sending this new version! One interesting thing is that you created a new patchset, instead of iterating on the same one, and this triggered a bug on b4[1]!
You also missed the changelog since v2, but AFAICS you addressed all comments from me, Joe and Petr, per [2].
For the two patches:
Reviewed-by: Marcos Paulo de Souza mpdesouza@suse.com
[1]: https://github.com/mricon/b4/issues/58 [2]: https://lore.kernel.org/live-patching/b2637bad-9022-496a-9b83-0d348a6350b4@g...
base-commit: 848e076317446f9c663771ddec142d7c2eb4cb43 change-id: 20250306-ftrace-sftest-livepatch-60d9dc472235
Best regards,
linux-kselftest-mirror@lists.linaro.org
-
Filipe Xavier -
Marcos Paulo de Souza -
Miroslav Benes