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author | Steven Rostedt <srostedt@redhat.com> | 2008-12-02 23:50:06 -0500 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-12-03 08:56:27 +0100 |
commit | 62679efe0a5f02987a621942afc5979a80a6ca5a (patch) | |
tree | 6d10f9e3f8804ee6414f672695b4f15f78377c21 /arch/x86/kernel | |
parent | e49dc19c6a19ea112fcb94b7c62ec62cdd5c08aa (diff) | |
download | op-kernel-dev-62679efe0a5f02987a621942afc5979a80a6ca5a.zip op-kernel-dev-62679efe0a5f02987a621942afc5979a80a6ca5a.tar.gz |
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/kernel')
-rw-r--r-- | 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; } |