[PATCH] selftests/ftrace: Account for fprobe attachment at creation

Cao Ruichuang
2026-04-07T11:58:33Z

add_remove_fprobe.tc assumes that enabling an fprobe event is what adds
its target function to enabled_functions.

On the current kernel, the fprobe target already appears in
enabled_functions as soon as the event is created, and enabling the
event does not change that count again. That makes the test fail even
though the event lifecycle itself works.

Record the attachment baseline after creating the probe events and only
check that enabling them keeps the expected functions attached. The
cleanup checks still verify that removing the events returns
enabled_functions to its original state.

Signed-off-by: Cao Ruichuang <create0818@163.com>
---
.../test.d/dynevent/add_remove_fprobe.tc | 28 +++++++++++++------
1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_fprobe.tc b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_fprobe.tc
index 47067a5e3..ff08bd1ac 100644
--- a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_fprobe.tc
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_fprobe.tc
@@ -26,23 +26,29 @@ grep -q myevent2 dynamic_events
grep -q myevent3 dynamic_events
test -d events/fprobes/myevent1
test -d events/fprobes/myevent2
-
-echo 1 > events/fprobes/myevent1/enable
-# Make sure the event is attached.
grep -q $PLACE enabled_functions
+grep -q $PLACE2 enabled_functions
cnt=`cat enabled_functions | wc -l`
-if [ $cnt -eq $ocnt ]; then
+if [ $cnt -le $ocnt ]; then
+ exit_fail
+fi
+
+echo 1 > events/fprobes/myevent1/enable
+cnt1=`cat enabled_functions | wc -l`
+if [ $cnt1 -ne $cnt ]; then
exit_fail
fi

echo 1 > events/fprobes/myevent2/enable
cnt2=`cat enabled_functions | wc -l`
+if [ $cnt2 -ne $cnt1 ]; then
+ exit_fail
+fi

echo 1 > events/fprobes/myevent3/enable
-# If the function is different, the attached function should be increased
grep -q $PLACE2 enabled_functions
cnt=`cat enabled_functions | wc -l`
-if [ $cnt -eq $cnt2 ]; then
+if [ $cnt -ne $cnt2 ]; then
exit_fail
fi

@@ -62,11 +68,15 @@ if [ $cnt -ne $ocnt ]; then
fi

echo "f:myevent4 $PLACE" >> dynamic_events
+grep -q $PLACE enabled_functions
+cnt=`cat enabled_functions | wc -l`
+if [ $cnt -le $ocnt ]; then
+ exit_fail
+fi

echo 1 > events/fprobes/myevent4/enable
-# Should only have one enabled
-cnt=`cat enabled_functions | wc -l`
-if [ $cnt -ne $((ocnt + 1)) ]; then
+cnt2=`cat enabled_functions | wc -l`
+if [ $cnt2 -ne $cnt ]; then
exit_fail
fi

--
2.39.5 (Apple Git-154)