Commit 62679efe authored by Steven Rostedt's avatar Steven Rostedt Committed by Ingo Molnar
Browse files

ftrace: add checks on ret stack in function graph 



Import: robustness checks

Add more checks in the function graph code to detect errors and
perhaps print out better information if a bug happens.

Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent e49dc19c

arch/x86/kernel/ftrace.c

+17 −0
Original line number Diff line number Diff line
@@ -420,6 +420,15 @@ static void pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret) 
	int index;



	index = current->curr_ret_stack;



	if (unlikely(index < 0)) {

		ftrace_graph_stop();

		WARN_ON(1);

		/* Might as well panic, otherwise we have no where to go */

		*ret = (unsigned long)panic;

		return;

	}



	*ret = current->ret_stack[index].ret;

	trace->func = current->ret_stack[index].func;

	trace->calltime = current->ret_stack[index].calltime;
@@ -427,6 +436,7 @@ static void pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret) 
	trace->depth = index;

	barrier();

	current->curr_ret_stack--;



}



/*
@@ -442,6 +452,13 @@ unsigned long ftrace_return_to_handler(void) 
	trace.rettime = cpu_clock(raw_smp_processor_id());

	ftrace_graph_return(&trace);



	if (unlikely(!ret)) {

		ftrace_graph_stop();

		WARN_ON(1);

		/* Might as well panic. What else to do? */

		ret = (unsigned long)panic;

	}



	return ret;

}