[PATCH 4.14 013/106] tracing: Fix pid filtering when triggers are attached

Greg Kroah-Hartman
2021-12-06T15:15:18Z

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

commit a55f224ff5f238013de8762c4287117e47b86e22 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/trace/trace.h | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)

--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1363,14 +1363,26 @@ __event_trigger_test_discard(struct trac
if (eflags & EVENT_FILE_FL_TRIGGER_COND)
*tt = event_triggers_call(file, entry);

- 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;
}

/**