The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6cb206508b621a9a0a2c35b60540e399225c8243 Mon Sep 17 00:00:00 2001

From: "Steven Rostedt (VMware)" rostedt@goodmis.org Date: Fri, 26 Nov 2021 13:35:26 -0500 Subject: [PATCH] tracing: Check pid filtering when creating events

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

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);