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ftrace: add checks on ret stack in function graph

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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: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Steven Rostedt 2008-12-02 23:50:06 -05:00 committed by Ingo Molnar
parent e49dc19c6a
commit 62679efe0a
1 changed files with 17 additions and 0 deletions
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17
arch/x86/kernel/ftrace.c
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@ -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;
}