lkml.org 
[lkml]   [2008]   [Dec]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[PATCH 5/5] ftrace: add checks on ret stack in function graph
    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
    --


    \
     
     \ /
      Last update: 2008-12-03 05:55    [W:0.042 / U:120.156 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site