[for-next][PATCH] tracing: Apply trace_clock changes to instance max buffer

From: Steven Rostedt
Date: Thu Sep 07 2017 - 08:47:24 EST


git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
for-next

Head SHA1: 170b3b1050e28d1ba0700e262f0899ffa4fccc52


Baohong Liu (1):
tracing: Apply trace_clock changes to instance max buffer

----
kernel/trace/trace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
---------------------------
commit 170b3b1050e28d1ba0700e262f0899ffa4fccc52
Author: Baohong Liu <baohong.liu@xxxxxxxxx>
Date: Tue Sep 5 16:57:19 2017 -0500

tracing: Apply trace_clock changes to instance max buffer

Currently trace_clock timestamps are applied to both regular and max
buffers only for global trace. For instance trace, trace_clock
timestamps are applied only to regular buffer. But, regular and max
buffers can be swapped, for example, following a snapshot. So, for
instance trace, bad timestamps can be seen following a snapshot.
Let's apply trace_clock timestamps to instance max buffer as well.

Link: http://lkml.kernel.org/r/ebdb168d0be042dcdf51f81e696b17fabe3609c1.1504642143.git.tom.zanussi@xxxxxxxxxxxxxxx

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 277ba0446 ("tracing: Add interface to allow multiple trace buffers")
Signed-off-by: Baohong Liu <baohong.liu@xxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 78842557eea0..5360b7aec57a 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6229,7 +6229,7 @@ static int tracing_set_clock(struct trace_array *tr, const char *clockstr)
tracing_reset_online_cpus(&tr->trace_buffer);

#ifdef CONFIG_TRACER_MAX_TRACE
- if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer)
+ if (tr->max_buffer.buffer)
ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
tracing_reset_online_cpus(&tr->max_buffer);
#endif