selftests: livepatch: test if ftrace can trace a livepatched function

JIRA: https://issues.redhat.com/browse/RHEL-114920

Conflicts:
	tools/testing/selftests/livepatch/test-ftrace.sh
	- cs-9 doesn't have upstream c4bbe83 ("livepatch: Move
	  tests from lib/livepatch to selftests/livepatch"), which
	  changed from using `modprobe` to `insmod`, update expected
	  dmesg accordingly.

commit 474eecc
Author: Filipe Xavier <felipeaggger@gmail.com>
Date:   Mon Mar 24 19:50:19 2025 -0300

    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 <felipeaggger@gmail.com>
    Acked-by: Miroslav Benes <mbenes@suse.cz>
    Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
    Reviewed-by: Petr Mladek <pmladek@suse.com>
    Tested-by: Petr Mladek <pmladek@suse.com>
    Link: https://lore.kernel.org/r/20250324-ftrace-sftest-livepatch-v3-2-d9d7cc386c75@gmail.com
    Signed-off-by: Petr Mladek <pmladek@suse.com>

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>

Author: joe-lawrence

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 "% modprobe $MOD_LIVEPATCH
+livepatch: enabling patch '$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