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authorSteven Rostedt <srostedt@redhat.com>2008-12-02 23:50:06 -0500
committerIngo Molnar <mingo@elte.hu>2008-12-03 08:56:27 +0100
commit62679efe0a5f02987a621942afc5979a80a6ca5a (patch)
tree6d10f9e3f8804ee6414f672695b4f15f78377c21 /arch/x86
parente49dc19c6a19ea112fcb94b7c62ec62cdd5c08aa (diff)
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: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/ftrace.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index d278ad2ebda..f98c4076a17 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -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;
}