From 48186febf17490820dc089172c58526664255417 Mon Sep 17 00:00:00 2001
From: Eugeni Dodonov <eugeni.dodonov@intel.com>
Date: Thu, 10 Nov 2011 11:12:10 -0200
Subject: [PATCH] tests: add test for kernel segmentation fault

As asked by Daniel Vetter, this is a tech which checks if we can cause
division by zero in kernel by reading the i915_emon_status debugfs
entry repeatably.

Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
---
 tests/Makefile.am        |  1 +
 tests/debugfs_emon_crash | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100755 tests/debugfs_emon_crash

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 525380ef..dffda411 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -56,6 +56,7 @@ TESTS_progs = \
 
 TESTS_scripts = \
 	debugfs_reader \
+	debugfs_emon_crash \
 	$(NULL)
 
 kernel_tests = \
diff --git a/tests/debugfs_emon_crash b/tests/debugfs_emon_crash
new file mode 100755
index 00000000..63e193d8
--- /dev/null
+++ b/tests/debugfs_emon_crash
@@ -0,0 +1,34 @@
+#!/bin/sh
+#
+# This check if we can crash the kernel with segmentation-fault
+# by reading /sys/kernel/debug/dri/0/i915_emon_status too quickly
+#
+
+if [ -d /debug/dri ] ; then
+	debugfs_path=/debug_dri
+fi
+
+if [ -d /sys/kernel/debug/dri ] ; then
+	debugfs_path=/sys/kernel/debug/dri
+fi
+
+i915_path=x
+for dir in `ls $debugfs_path` ; do
+	if [ -f $debugfs_path/$dir/i915_error_state ] ; then
+		i915_path=$debugfs_path/$dir
+		break
+	fi
+done
+
+if [ $i915_path = "x" ] ; then
+	echo i915 debugfs path not found.
+	exit 1
+fi
+
+for z in $(seq 1 1000); do
+	cat $i915_path/i915_emon_status > /dev/null
+done
+
+# If we got here, we haven't crashed
+
+exit 0