Commit 05ce5818 authored Mar 24, 2009 by Steven Rostedt

function-graph: prevent more than one tracer registering



Impact: prevent crash due to multiple function graph tracers

The function graph tracer can currently only handle a single tracer
being registered. If another tracer registers with the function
graph tracer it can crash the system.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>

parent 5d1a03dc

kernel/trace/ftrace.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -2643,6 +2643,12 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,

		mutex_lock(&ftrace_lock);

		/* we currently allow only one tracer registered at a time */
		if (atomic_read(&ftrace_graph_active)) {
		ret = -EBUSY;
		goto out;
		}

		ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
		register_pm_notifier(&ftrace_suspend_notifier);