[PATCH v5 8/9] selftests/ftrace: Add BTF fields access testcases

Masami Hiramatsu (Google)
2023-08-07T02:55:53Z

Add test cases for accessing the data structure fields using BTF info.
This includes the field access from parameters and retval, and accessing
string information.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
---
Changes in v2:
- Use '$retval' instead of 'retval'.
- Add a test that use both '$retval' and '$arg1' for fprobe.
Changes in v3:
- Change a test case with a numeric value.
- Add a test case with mixed '.' and '->' operators.
Changes in v5:
- Check fields access availability.
---
.../ftrace/test.d/dynevent/add_remove_btfarg.tc | 20 ++++++++++++++++++++
.../ftrace/test.d/dynevent/fprobe_syntax_errors.tc | 8 ++++++++
2 files changed, 28 insertions(+)

diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc
index f34b14ef9781..b9c21a81d248 100644
--- a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc
@@ -5,6 +5,7 @@

KPROBES=
FPROBES=
+FIELDS=

if grep -qF "p[:[<group>/][<event>]] <place> [<args>]" README ; then
KPROBES=yes
@@ -12,6 +13,9 @@ fi
if grep -qF "f[:[<group>/][<event>]] <func-name>[%return] [<args>]" README ; then
FPROBES=yes
fi
+if grep -qF "<argname>[->field[->field|.field...]]" README ; then
+ FIELDS=yes
+fi

if [ -z "$KPROBES" -a -z "$FPROBES" ] ; then
exit_unsupported
@@ -21,6 +25,9 @@ echo 0 > events/enable
echo > dynamic_events

TP=kfree
+TP2=kmem_cache_alloc
+TP3=getname_flags
+TP4=sched_wakeup

if [ "$FPROBES" ] ; then
echo "f:fpevent $TP object" >> dynamic_events
@@ -33,6 +40,7 @@ echo > dynamic_events

echo "f:fpevent $TP "'$arg1' >> dynamic_events
grep -q "fpevent.*object=object" dynamic_events
+
echo > dynamic_events

echo "f:fpevent $TP "'$arg*' >> dynamic_events
@@ -45,6 +53,18 @@ fi

echo > dynamic_events

+if [ "$FIELDS" ] ; then
+echo "t:tpevent ${TP2} obj_size=s->object_size" >> dynamic_events
+echo "f:fpevent ${TP3}%return path=\$retval->name:string" >> dynamic_events
+echo "t:tpevent2 ${TP4} p->se.group_node.next->prev" >> dynamic_events
+
+grep -q "tpevent .*obj_size=s->object_size" dynamic_events
+grep -q "fpevent.*path=\$retval->name:string" dynamic_events
+grep -q 'tpevent2 .*p->se.group_node.next->prev' dynamic_events
+
+echo > dynamic_events
+fi
+
if [ "$KPROBES" ] ; then
echo "p:kpevent $TP object" >> dynamic_events
grep -q "kpevent.*object=object" dynamic_events
diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
index 72563b2e0812..20e42c030095 100644
--- a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
@@ -103,6 +103,14 @@ check_error 'f vfs_read%return ^$arg*' # NOFENTRY_ARGS
check_error 'f vfs_read ^hoge' # NO_BTFARG
check_error 'f kfree ^$arg10' # NO_BTFARG (exceed the number of parameters)
check_error 'f kfree%return ^$retval' # NO_RETVAL
+
+if grep -qF "<argname>[->field[->field|.field...]]" README ; then
+check_error 'f vfs_read%return $retval->^foo' # NO_PTR_STRCT
+check_error 'f vfs_read file->^foo' # NO_BTF_FIELD
+check_error 'f vfs_read file^-.foo' # BAD_HYPHEN
+check_error 'f vfs_read ^file:string' # BAD_TYPE4STR
+fi
+
else
check_error 'f vfs_read ^$arg*' # NOSUP_BTFARG
check_error 't kfree ^$arg*' # NOSUP_BTFARG