[for-linus][PATCH 0/2] tracing: Updates to 5.16-rc2

[for-linus][PATCH 0/2] tracing: Updates to 5.16-rc2

[Steven Rostedt]

Two fixes to event pid filtering:

- Have created events reflect the current state of pid filtering

- Test pid filtering on discard test of recorded logic.
  (Also clean up the if statement to be easier to read).


Steven Rostedt (VMware) (2):
      tracing: Check pid filtering when creating events
      tracing: Fix pid filtering when triggers are attached

----
 kernel/trace/trace.h        | 24 ++++++++++++++++++------
 kernel/trace/trace_events.c | 12 ++++++++++++
 2 files changed, 30 insertions(+), 6 deletions(-)

[for-linus][PATCH 1/2] tracing: Check pid filtering when creating events

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

When pid filtering is activated in an instance, all of the events trace
files for that instance has the PID_FILTER flag set. This determines
whether or not pid filtering needs to be done on the event, otherwise the
event is executed as normal.

If pid filtering is enabled when an event is created (via a dynamic event
or modules), its flag is not updated to reflect the current state, and the
events are not filtered properly.

Cc: stable@vger.kernel.org
Fixes: 3fdaf80f4a836 ("tracing: Implement event pid filtering")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 4021b9a79f93..f8965fd50d3b 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2678,12 +2678,24 @@ static struct trace_event_file *
 trace_create_new_event(struct trace_event_call *call,
 		       struct trace_array *tr)
 {
+	struct trace_pid_list *no_pid_list;
+	struct trace_pid_list *pid_list;
 	struct trace_event_file *file;
+	unsigned int first;
 
 	file = kmem_cache_alloc(file_cachep, GFP_TRACE);
 	if (!file)
 		return NULL;
 
+	pid_list = rcu_dereference_protected(tr->filtered_pids,
+					     lockdep_is_held(&event_mutex));
+	no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
+					     lockdep_is_held(&event_mutex));
+
+	if (!trace_pid_list_first(pid_list, &first) ||
+	    !trace_pid_list_first(pid_list, &first))
+		file->flags |= EVENT_FILE_FL_PID_FILTER;
+
 	file->event_call = call;
 	file->tr = tr;
 	atomic_set(&file->sm_ref, 0);
-- 
2.33.0

[for-linus][PATCH 2/2] tracing: Fix pid filtering when triggers are attached

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

If a event is filtered by pid and a trigger that requires processing of
the event to happen is a attached to the event, the discard portion does
not take the pid filtering into account, and the event will then be
recorded when it should not have been.

Cc: stable@vger.kernel.org
Fixes: 3fdaf80f4a836 ("tracing: Implement event pid filtering")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.h | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 6b60ab9475ed..38715aa6cfdf 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1366,14 +1366,26 @@ __event_trigger_test_discard(struct trace_event_file *file,
 	if (eflags & EVENT_FILE_FL_TRIGGER_COND)
 		*tt = event_triggers_call(file, buffer, entry, event);
 
-	if (test_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags) ||
-	    (unlikely(file->flags & EVENT_FILE_FL_FILTERED) &&
-	     !filter_match_preds(file->filter, entry))) {
-		__trace_event_discard_commit(buffer, event);
-		return true;
-	}
+	if (likely(!(file->flags & (EVENT_FILE_FL_SOFT_DISABLED |
+				    EVENT_FILE_FL_FILTERED |
+				    EVENT_FILE_FL_PID_FILTER))))
+		return false;
+
+	if (file->flags & EVENT_FILE_FL_SOFT_DISABLED)
+		goto discard;
+
+	if (file->flags & EVENT_FILE_FL_FILTERED &&
+	    !filter_match_preds(file->filter, entry))
+		goto discard;
+
+	if ((file->flags & EVENT_FILE_FL_PID_FILTER) &&
+	    trace_event_ignore_this_pid(file))
+		goto discard;
 
 	return false;
+ discard:
+	__trace_event_discard_commit(buffer, event);
+	return true;
 }
 
 /**
-- 
2.33.0