ftrace/kprobes: selftests: Check kretprobe maxactive is supported

Check the kretprobe maxactive is supported by kprobe_events
interface. To ensure the kernel feature, this changes ftrace
README to describe it.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 1122f15..dc3f91e 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4473,7 +4473,8 @@ static const char readme_msg[] =
 #endif
 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
        "\t  accepts: event-definitions (one definition per line)\n"
-       "\t   Format: p|r[:[<group>/]<event>] <place> [<args>]\n"
+       "\t   Format: p[:[<group>/]<event>] <place> [<args>]\n"
+       "\t           r[maxactive][:[<group>/]<event>] <place> [<args>]\n"
        "\t           -:[<group>/]<event>\n"
 #ifdef CONFIG_KPROBE_EVENTS
        "\t    place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_maxactive.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_maxactive.tc
index 57abdf1..7ec6f26 100644 (file)
--- a/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_maxactive.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kretprobe_maxactive.tc
@@ -2,6 +2,7 @@
 # description: Kretprobe dynamic event with maxactive
 
 [ -f kprobe_events ] || exit_unsupported # this is configurable
+grep -q 'r\[maxactive\]' README || exit_unsupported # this is older version
 
 echo > kprobe_events