Commit fb9f5ee9 authored Dec 13, 2022 by Steven Rostedt (Google)

tracing: Do not synchronize freeing of trigger filter on boot up

If a trigger filter on the kernel command line fails to apply (due to
syntax error), it will be freed. The freeing will call
tracepoint_synchronize_unregister(), but this is not needed during early
boot up, and will even trigger a lockdep splat.

Avoid calling the synchronization function when system_state is
SYSTEM_BOOTING.

Link: https://lore.kernel.org/linux-trace-kernel/20221213172429.7774f4ba@gandalf.local.home



Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

parent fab89a09

kernel/trace/trace_events_trigger.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -1085,7 +1085,13 @@ int set_trigger_filter(char *filter_str,
		rcu_assign_pointer(data->filter, filter);

		if (tmp) {
		/* Make sure the call is done with the filter */
		/*
		* Make sure the call is done with the filter.
		* It is possible that a filter could fail at boot up,
		* and then this path will be called. Avoid the synchronization
		* in that case.
		*/
		if (system_state != SYSTEM_BOOTING)
		tracepoint_synchronize_unregister();
		free_event_filter(tmp);
		}