[PATCH 2/5] ftrace perf: Move exclude_kernel tracepoint check to init event

[Jiri Olsa]

We suppress events with attr::exclude_kernel set when
the event is generated, so following capture will
give no warning but won't produce any data:

  $ sudo perf record -e sched:sched_switch:u ls
  $ sudo /perf script | wc -l
  0

Checking the attr::exclude_(kernel|user) at the event
init time and failing right away for tracepoints from
uprobes/kprobes and native ones:

  $ sudo perf record -e sched:sched_switch:u ls
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (sched:sched_switch).
  /bin/dmesg may provide additional information.
  No CONFIG_PERF_EVENTS=y kernel support configured?

  $ sudo perf record -e probe:sys_read:u ls
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (probe:sys_read).
  /bin/dmesg may provide additional information.
  No CONFIG_PERF_EVENTS=y kernel support configured?

  $ ./perf record -e probe_ex:main:k ./ex
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (probe_ex:main).
  /bin/dmesg may provide additional information.
  No CONFIG_PERF_EVENTS=y kernel support configured?

Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
 kernel/events/core.c            |  5 -----
 kernel/trace/trace_event_perf.c | 25 +++++++++++++++++++++++++
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index c15fd097af93..ca68fdcf47ce 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6898,11 +6898,6 @@ static int perf_tp_event_match(struct perf_event *event,
 {
 	if (event->hw.state & PERF_HES_STOPPED)
 		return 0;
-	/*
-	 * All tracepoints are from kernel-space.
-	 */
-	if (event->attr.exclude_kernel)
-		return 0;
 
 	if (!perf_tp_filter_match(event, data))
 		return 0;
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index e11108f1d197..6e6d4052f398 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -185,11 +185,36 @@ static void perf_trace_event_close(struct perf_event *p_event)
 	tp_event->class->reg(tp_event, TRACE_REG_PERF_CLOSE, p_event);
 }
 
+static int perf_trace_event_attr(struct trace_event_call *tp_event,
+				 struct perf_event *event)
+{
+	/*
+	 * All tracepoints and kprobes are from kernel-space.
+	 */
+	if (((tp_event->flags & TRACE_EVENT_FL_TRACEPOINT) ||
+	     (tp_event->flags & TRACE_EVENT_FL_KPROBE)) &&
+	     event->attr.exclude_kernel)
+		return -EINVAL;
+
+	/*
+	 * All uprobes are from user-space.
+	 */
+	if ((tp_event->flags & TRACE_EVENT_FL_UPROBE) &&
+	    event->attr.exclude_user)
+		return -EINVAL;
+
+	return 0;
+}
+
 static int perf_trace_event_init(struct trace_event_call *tp_event,
 				 struct perf_event *p_event)
 {
 	int ret;
 
+	ret = perf_trace_event_attr(tp_event, p_event);
+	if (ret)
+		return ret;
+
 	ret = perf_trace_event_perm(tp_event, p_event);
 	if (ret)
 		return ret;
-- 
2.4.3