1#!/bin/bash 2# SPDX-License-Identifier: GPL-2.0-or-later 3 4TIMEOUT=30 5 6DEBUFS_DIR=`cat /proc/mounts | grep debugfs | awk '{print $2}'` 7if [ ! -e "$DEBUFS_DIR" ] 8then 9 echo "debugfs not found, skipping" 1>&2 10 exit 4 11fi 12 13if [ ! -e "$DEBUFS_DIR/tracing/current_tracer" ] 14then 15 echo "Tracing files not found, skipping" 1>&2 16 exit 4 17fi 18 19 20echo "Testing for spurious faults when mapping kernel memory..." 21 22if grep -q "FUNCTION TRACING IS CORRUPTED" "$DEBUFS_DIR/tracing/trace" 23then 24 echo "FAILED: Ftrace already dead. Probably due to a spurious fault" 1>&2 25 exit 1 26fi 27 28dmesg -C 29START_TIME=`date +%s` 30END_TIME=`expr $START_TIME + $TIMEOUT` 31while [ `date +%s` -lt $END_TIME ] 32do 33 echo function > $DEBUFS_DIR/tracing/current_tracer 34 echo nop > $DEBUFS_DIR/tracing/current_tracer 35 if dmesg | grep -q 'ftrace bug' 36 then 37 break 38 fi 39done 40 41echo nop > $DEBUFS_DIR/tracing/current_tracer 42if dmesg | grep -q 'ftrace bug' 43then 44 echo "FAILED: Mapping kernel memory causes spurious faults" 1>&2 45 exit 1 46else 47 echo "OK: Mapping kernel memory does not cause spurious faults" 48 exit 0 49fi 50