[PATCH 1/3] tracing: Treat recording comm for idle task as a success

From: Joel Fernandes
Date: Thu Jul 06 2017 - 19:00:44 EST


Currently we stop recording comm for non-idle tasks when switching from/to idle
task since we treat that as a record failure. Fix that by treat recording of
comm for idle task as a success.

Cc: kernel-team@xxxxxxxxxxx
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Reported-by: Michael Sartain <mikesart@xxxxxxxxx>
Signed-off-by: Joel Fernandes <joelaf@xxxxxxxxxx>
---
kernel/trace/trace.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c579dea4a0eb..7a0c493723a9 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1916,7 +1916,11 @@ static int trace_save_cmdline(struct task_struct *tsk)
{
unsigned pid, idx;

- if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
+ /* treat recording of idle task as a success */
+ if (!tsk->pid)
+ return 1;
+
+ if (unlikely(tsk->pid > PID_MAX_DEFAULT))
return 0;

/*
--
2.13.2.725.g09c95d1e9-goog