From 0ded5174e976e2b2a354fe38abf1ebf4492c6dc3 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Mon, 23 May 2016 15:06:30 -0400
Subject: ftracetest: Fix hist unsupported result in hist selftests

When histograms are not configured in the kernel, the ftracetest histogram
selftests should return "unsupported" and not "Failed". To detect this, the
test scripts have:

 FEATURE=`grep hist events/sched/sched_process_fork/trigger`
 if [ -z "$FEATURE" ]; then
     echo "hist trigger is not supported"
     exit_unsupported
 fi

The problem is that '-e' is in effect and any error will cause the program
to terminate. The grep for 'hist' fails, because it is not compiled it (thus
unsupported), but because grep has an error code for failing to find the
string, it causes the program to terminate, and is marked as a failed test.

Namhyung Kim recommended to test for the "hist" file located in
events/sched/sched_process_fork/hist instead, as it is more inline with the
other checks. As the hist file is only created if the histogram feature is
enabled, that is a valid check.

Link: http://lkml.kernel.org/r/20160523151538.4ea9ce0c@gandalf.local.home

Suggested-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: 76929ab51f0ee ("kselftests/ftrace: Add hist trigger testcases")
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-mod.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-mod.tc
index c2b61c4..0bf5085 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-mod.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-mod.tc
@@ -23,15 +23,14 @@ if [ ! -f events/sched/sched_process_fork/trigger ]; then
     exit_unsupported
 fi
 
-reset_tracer
-do_reset
-
-FEATURE=`grep hist events/sched/sched_process_fork/trigger`
-if [ -z "$FEATURE" ]; then
+if [ ! -f events/sched/sched_process_fork/hist ]; then
     echo "hist trigger is not supported"
     exit_unsupported
 fi
 
+reset_tracer
+do_reset
+
 echo "Test histogram with execname modifier"
 
 echo 'hist:keys=common_pid.execname' > events/sched/sched_process_fork/trigger
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist.tc
index b2902d4..a00184c 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-hist.tc
@@ -23,15 +23,14 @@ if [ ! -f events/sched/sched_process_fork/trigger ]; then
     exit_unsupported
 fi
 
-reset_tracer
-do_reset
-
-FEATURE=`grep hist events/sched/sched_process_fork/trigger`
-if [ -z "$FEATURE" ]; then
+if [ ! -f events/sched/sched_process_fork/hist ]; then
     echo "hist trigger is not supported"
     exit_unsupported
 fi
 
+reset_tracer
+do_reset
+
 echo "Test histogram basic tigger"
 
 echo 'hist:keys=parent_pid:vals=child_pid' > events/sched/sched_process_fork/trigger
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-multihist.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-multihist.tc
index 03c4a46..3478b00 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/trigger-multihist.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-multihist.tc
@@ -23,15 +23,14 @@ if [ ! -f events/sched/sched_process_fork/trigger ]; then
     exit_unsupported
 fi
 
-reset_tracer
-do_reset
-
-FEATURE=`grep hist events/sched/sched_process_fork/trigger`
-if [ -z "$FEATURE" ]; then
+if [ ! -f events/sched/sched_process_fork/hist ]; then
     echo "hist trigger is not supported"
     exit_unsupported
 fi
 
+reset_tracer
+do_reset
+
 reset_trigger
 
 echo "Test histogram multiple tiggers"
-- 
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