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Commit d3d9acf6 authored by Tejun Heo's avatar Tejun Heo Committed by Steven Rostedt
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trace_events_filter: Use rcu_assign_pointer() when setting ftrace_event_call->filter 

ftrace_event_call->filter is sched RCU protected but didn't use
rcu_assign_pointer().  Use it.

TODO: Add proper __rcu annotation to call->filter and all its users.

-v2: Use RCU_INIT_POINTER() for %NULL clearing as suggested by Eric.

Link: http://lkml.kernel.org/r/20111123164949.GA29639@google.com



Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@kernel.org # (2.6.39+)
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 4a1dba72

kernel/trace/trace_events_filter.c

+3 −3
Original line number Diff line number Diff line
@@ -1686,7 +1686,7 @@ static int replace_system_preds(struct event_subsystem *system, 
		 * replace the filter for the call.

		 */

		filter = call->filter;

		call->filter = filter_item->filter;

		rcu_assign_pointer(call->filter, filter_item->filter);

		filter_item->filter = filter;



		fail = false;
@@ -1741,7 +1741,7 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string) 
		filter = call->filter;

		if (!filter)

			goto out_unlock;

		call->filter = NULL;

		RCU_INIT_POINTER(call->filter, NULL);

		/* Make sure the filter is not being used */

		synchronize_sched();

		__free_filter(filter);
@@ -1782,7 +1782,7 @@ out: 
	 * string

	 */

	tmp = call->filter;

	call->filter = filter;

	rcu_assign_pointer(call->filter, filter);

	if (tmp) {

		/* Make sure the call is done with the filter */

		synchronize_sched();