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    Subject[PATCH 3.16 225/366] tracing: Fix missing return symbol in function_graph output
    3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Changbin Du <changbin.du@intel.com>

    commit 1fe4293f4b8de75824935f8d8e9a99c7fc6873da upstream.

    The function_graph tracer does not show the interrupt return marker for the
    leaf entry. On leaf entries, we see an unbalanced interrupt marker (the
    interrupt was entered, but nevern left).

    Before:
    1) | SyS_write() {
    1) | __fdget_pos() {
    1) 0.061 us | __fget_light();
    1) 0.289 us | }
    1) | vfs_write() {
    1) 0.049 us | rw_verify_area();
    1) + 15.424 us | __vfs_write();
    1) ==========> |
    1) 6.003 us | smp_apic_timer_interrupt();
    1) 0.055 us | __fsnotify_parent();
    1) 0.073 us | fsnotify();
    1) + 23.665 us | }
    1) + 24.501 us | }

    After:
    0) | SyS_write() {
    0) | __fdget_pos() {
    0) 0.052 us | __fget_light();
    0) 0.328 us | }
    0) | vfs_write() {
    0) 0.057 us | rw_verify_area();
    0) | __vfs_write() {
    0) ==========> |
    0) 8.548 us | smp_apic_timer_interrupt();
    0) <========== |
    0) + 36.507 us | } /* __vfs_write */
    0) 0.049 us | __fsnotify_parent();
    0) 0.066 us | fsnotify();
    0) + 50.064 us | }
    0) + 50.952 us | }

    Link: http://lkml.kernel.org/r/1517413729-20411-1-git-send-email-changbin.du@intel.com

    Fixes: f8b755ac8e0cc ("tracing/function-graph-tracer: Output arrows signal on hardirq call/return")
    Signed-off-by: Changbin Du <changbin.du@intel.com>
    Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
    [bwh: Backported to 3.16: Propagate return of TRACE_TYPE_PARTIAL_LINE from
    print_graph_irq()]
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    kernel/trace/trace_functions_graph.c | 5 ++++-
    1 file changed, 4 insertions(+), 1 deletion(-)

    --- a/kernel/trace/trace_functions_graph.c
    +++ b/kernel/trace/trace_functions_graph.c
    @@ -828,6 +828,7 @@ print_graph_entry_leaf(struct trace_iter
    struct ftrace_graph_ret *graph_ret;
    struct ftrace_graph_ent *call;
    unsigned long long duration;
    + int cpu = iter->cpu;
    int ret;
    int i;

    @@ -837,7 +838,6 @@ print_graph_entry_leaf(struct trace_iter

    if (data) {
    struct fgraph_cpu_data *cpu_data;
    - int cpu = iter->cpu;

    cpu_data = per_cpu_ptr(data->cpu_data, cpu);

    @@ -874,6 +874,11 @@ print_graph_entry_leaf(struct trace_iter
    if (!ret)
    return TRACE_TYPE_PARTIAL_LINE;

    + ret = print_graph_irq(iter, graph_ret->func, TRACE_GRAPH_RET,
    + cpu, iter->ent->pid, flags);
    + if (ret == TRACE_TYPE_PARTIAL_LINE)
    + return ret;
    +
    return TRACE_TYPE_HANDLED;
    }

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