Messages in this thread Patch in this message | | | Date | Tue, 02 Dec 2008 23:50:06 -0500 | From | Steven Rostedt <> | Subject | [PATCH 5/5] ftrace: add checks on ret stack in function graph |
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From: Steven Rostedt <srostedt@redhat.com>
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> --- arch/x86/kernel/ftrace.c | 17 +++++++++++++++++ 1 files changed, 17 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index d278ad2..f98c407 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; } -- 1.5.6.5 --
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