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