1 files changed, 49 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/mm/stress_code_patching.sh b/tools/testing/selftests/powerpc/mm/stress_code_patching.sh
new file mode 100755
index 000000000000..e454509659f6
--- /dev/null
+++ b/tools/testing/selftests/powerpc/mm/stress_code_patching.sh
@@ -0,0 +1,49 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+TIMEOUT=30
+
+DEBUFS_DIR=`cat /proc/mounts | grep debugfs | awk '{print $2}'`
+if [ ! -e "$DEBUFS_DIR" ]
+then
+	echo "debugfs not found, skipping" 1>&2
+	exit 4
+fi
+
+if [ ! -e "$DEBUFS_DIR/tracing/current_tracer" ]
+then
+	echo "Tracing files not found, skipping" 1>&2
+	exit 4
+fi
+
+
+echo "Testing for spurious faults when mapping kernel memory..."
+
+if grep -q "FUNCTION TRACING IS CORRUPTED" "$DEBUFS_DIR/tracing/trace"
+then
+	echo "FAILED: Ftrace already dead. Probably due to a spurious fault" 1>&2
+	exit 1
+fi
+
+dmesg -C
+START_TIME=`date +%s`
+END_TIME=`expr $START_TIME + $TIMEOUT`
+while [ `date +%s` -lt $END_TIME ]
+do
+	echo function > $DEBUFS_DIR/tracing/current_tracer
+	echo nop > $DEBUFS_DIR/tracing/current_tracer
+	if dmesg | grep -q 'ftrace bug'
+	then
+		break
+	fi
+done
+
+echo nop > $DEBUFS_DIR/tracing/current_tracer
+if dmesg | grep -q 'ftrace bug'
+then
+	echo "FAILED: Mapping kernel memory causes spurious faults" 1>&2
+	exit 1
+else
+	echo "OK: Mapping kernel memory does not cause spurious faults"
+	exit 0
+fi