releases/4.9.52/tracing-apply-trace_clock-changes-to-instance-max-buffer.patch

   1 From 170b3b1050e28d1ba0700e262f0899ffa4fccc52 Mon Sep 17 00:00:00 2001
   2 From: Baohong Liu <baohong.liu@intel.com>
   3 Date: Tue, 5 Sep 2017 16:57:19 -0500
   4 Subject: tracing: Apply trace_clock changes to instance max buffer
   5
   6 From: Baohong Liu <baohong.liu@intel.com>
   7
   8 commit 170b3b1050e28d1ba0700e262f0899ffa4fccc52 upstream.
   9
  10 Currently trace_clock timestamps are applied to both regular and max
  11 buffers only for global trace. For instance trace, trace_clock
  12 timestamps are applied only to regular buffer. But, regular and max
  13 buffers can be swapped, for example, following a snapshot. So, for
  14 instance trace, bad timestamps can be seen following a snapshot.
  15 Let's apply trace_clock timestamps to instance max buffer as well.
  16
  17 Link: http://lkml.kernel.org/r/ebdb168d0be042dcdf51f81e696b17fabe3609c1.1504642143.git.tom.zanussi@linux.intel.com
  18
  19 Fixes: 277ba0446 ("tracing: Add interface to allow multiple trace buffers")
  20 Signed-off-by: Baohong Liu <baohong.liu@intel.com>
  21 Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
  22 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  23
  24 ---
  25  kernel/trace/trace.c |    2 +-
  26  1 file changed, 1 insertion(+), 1 deletion(-)
  27
  28 --- a/kernel/trace/trace.c
  29 +++ b/kernel/trace/trace.c
  30 @@ -5664,7 +5664,7 @@ static int tracing_set_clock(struct trac
  31         tracing_reset_online_cpus(&tr->trace_buffer);
  32
  33  #ifdef CONFIG_TRACER_MAX_TRACE
  34 -       if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer)
  35 +       if (tr->max_buffer.buffer)
  36                 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
  37         tracing_reset_online_cpus(&tr->max_buffer);
  38  #endif