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

From: Filipe Xavier
Date: Fri Mar 14 2025 - 15:00:34 EST


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