Loading...
1Notifier error injection
2========================
3
4Notifier error injection provides the ability to inject artificial errors to
5specified notifier chain callbacks. It is useful to test the error handling of
6notifier call chain failures which is rarely executed. There are kernel
7modules that can be used to test the following notifiers.
8
9 * CPU notifier
10 * PM notifier
11 * Memory hotplug notifier
12 * powerpc pSeries reconfig notifier
13 * Netdevice notifier
14
15CPU notifier error injection module
16-----------------------------------
17This feature can be used to test the error handling of the CPU notifiers by
18injecting artificial errors to CPU notifier chain callbacks.
19
20If the notifier call chain should be failed with some events notified, write
21the error code to debugfs interface
22/sys/kernel/debug/notifier-error-inject/cpu/actions/<notifier event>/error
23
24Possible CPU notifier events to be failed are:
25
26 * CPU_UP_PREPARE
27 * CPU_UP_PREPARE_FROZEN
28 * CPU_DOWN_PREPARE
29 * CPU_DOWN_PREPARE_FROZEN
30
31Example1: Inject CPU offline error (-1 == -EPERM)
32
33 # cd /sys/kernel/debug/notifier-error-inject/cpu
34 # echo -1 > actions/CPU_DOWN_PREPARE/error
35 # echo 0 > /sys/devices/system/cpu/cpu1/online
36 bash: echo: write error: Operation not permitted
37
38Example2: inject CPU online error (-2 == -ENOENT)
39
40 # echo -2 > actions/CPU_UP_PREPARE/error
41 # echo 1 > /sys/devices/system/cpu/cpu1/online
42 bash: echo: write error: No such file or directory
43
44PM notifier error injection module
45----------------------------------
46This feature is controlled through debugfs interface
47/sys/kernel/debug/notifier-error-inject/pm/actions/<notifier event>/error
48
49Possible PM notifier events to be failed are:
50
51 * PM_HIBERNATION_PREPARE
52 * PM_SUSPEND_PREPARE
53 * PM_RESTORE_PREPARE
54
55Example: Inject PM suspend error (-12 = -ENOMEM)
56
57 # cd /sys/kernel/debug/notifier-error-inject/pm/
58 # echo -12 > actions/PM_SUSPEND_PREPARE/error
59 # echo mem > /sys/power/state
60 bash: echo: write error: Cannot allocate memory
61
62Memory hotplug notifier error injection module
63----------------------------------------------
64This feature is controlled through debugfs interface
65/sys/kernel/debug/notifier-error-inject/memory/actions/<notifier event>/error
66
67Possible memory notifier events to be failed are:
68
69 * MEM_GOING_ONLINE
70 * MEM_GOING_OFFLINE
71
72Example: Inject memory hotplug offline error (-12 == -ENOMEM)
73
74 # cd /sys/kernel/debug/notifier-error-inject/memory
75 # echo -12 > actions/MEM_GOING_OFFLINE/error
76 # echo offline > /sys/devices/system/memory/memoryXXX/state
77 bash: echo: write error: Cannot allocate memory
78
79powerpc pSeries reconfig notifier error injection module
80--------------------------------------------------------
81This feature is controlled through debugfs interface
82/sys/kernel/debug/notifier-error-inject/pSeries-reconfig/actions/<notifier event>/error
83
84Possible pSeries reconfig notifier events to be failed are:
85
86 * PSERIES_RECONFIG_ADD
87 * PSERIES_RECONFIG_REMOVE
88 * PSERIES_DRCONF_MEM_ADD
89 * PSERIES_DRCONF_MEM_REMOVE
90
91Netdevice notifier error injection module
92----------------------------------------------
93This feature is controlled through debugfs interface
94/sys/kernel/debug/notifier-error-inject/netdev/actions/<notifier event>/error
95
96Netdevice notifier events which can be failed are:
97
98 * NETDEV_REGISTER
99 * NETDEV_CHANGEMTU
100 * NETDEV_CHANGENAME
101 * NETDEV_PRE_UP
102 * NETDEV_PRE_TYPE_CHANGE
103 * NETDEV_POST_INIT
104 * NETDEV_PRECHANGEMTU
105 * NETDEV_PRECHANGEUPPER
106 * NETDEV_CHANGEUPPER
107
108Example: Inject netdevice mtu change error (-22 == -EINVAL)
109
110 # cd /sys/kernel/debug/notifier-error-inject/netdev
111 # echo -22 > actions/NETDEV_CHANGEMTU/error
112 # ip link set eth0 mtu 1024
113 RTNETLINK answers: Invalid argument
114
115For more usage examples
116-----------------------
117There are tools/testing/selftests using the notifier error injection features
118for CPU and memory notifiers.
119
120 * tools/testing/selftests/cpu-hotplug/on-off-test.sh
121 * tools/testing/selftests/memory-hotplug/on-off-test.sh
122
123These scripts first do simple online and offline tests and then do fault
124injection tests if notifier error injection module is available.
1Notifier error injection
2========================
3
4Notifier error injection provides the ability to inject artificial errors to
5specified notifier chain callbacks. It is useful to test the error handling of
6notifier call chain failures which is rarely executed. There are kernel
7modules that can be used to test the following notifiers.
8
9 * PM notifier
10 * Memory hotplug notifier
11 * powerpc pSeries reconfig notifier
12 * Netdevice notifier
13
14PM notifier error injection module
15----------------------------------
16This feature is controlled through debugfs interface
17/sys/kernel/debug/notifier-error-inject/pm/actions/<notifier event>/error
18
19Possible PM notifier events to be failed are:
20
21 * PM_HIBERNATION_PREPARE
22 * PM_SUSPEND_PREPARE
23 * PM_RESTORE_PREPARE
24
25Example: Inject PM suspend error (-12 = -ENOMEM)
26
27 # cd /sys/kernel/debug/notifier-error-inject/pm/
28 # echo -12 > actions/PM_SUSPEND_PREPARE/error
29 # echo mem > /sys/power/state
30 bash: echo: write error: Cannot allocate memory
31
32Memory hotplug notifier error injection module
33----------------------------------------------
34This feature is controlled through debugfs interface
35/sys/kernel/debug/notifier-error-inject/memory/actions/<notifier event>/error
36
37Possible memory notifier events to be failed are:
38
39 * MEM_GOING_ONLINE
40 * MEM_GOING_OFFLINE
41
42Example: Inject memory hotplug offline error (-12 == -ENOMEM)
43
44 # cd /sys/kernel/debug/notifier-error-inject/memory
45 # echo -12 > actions/MEM_GOING_OFFLINE/error
46 # echo offline > /sys/devices/system/memory/memoryXXX/state
47 bash: echo: write error: Cannot allocate memory
48
49powerpc pSeries reconfig notifier error injection module
50--------------------------------------------------------
51This feature is controlled through debugfs interface
52/sys/kernel/debug/notifier-error-inject/pSeries-reconfig/actions/<notifier event>/error
53
54Possible pSeries reconfig notifier events to be failed are:
55
56 * PSERIES_RECONFIG_ADD
57 * PSERIES_RECONFIG_REMOVE
58 * PSERIES_DRCONF_MEM_ADD
59 * PSERIES_DRCONF_MEM_REMOVE
60
61Netdevice notifier error injection module
62----------------------------------------------
63This feature is controlled through debugfs interface
64/sys/kernel/debug/notifier-error-inject/netdev/actions/<notifier event>/error
65
66Netdevice notifier events which can be failed are:
67
68 * NETDEV_REGISTER
69 * NETDEV_CHANGEMTU
70 * NETDEV_CHANGENAME
71 * NETDEV_PRE_UP
72 * NETDEV_PRE_TYPE_CHANGE
73 * NETDEV_POST_INIT
74 * NETDEV_PRECHANGEMTU
75 * NETDEV_PRECHANGEUPPER
76 * NETDEV_CHANGEUPPER
77
78Example: Inject netdevice mtu change error (-22 == -EINVAL)
79
80 # cd /sys/kernel/debug/notifier-error-inject/netdev
81 # echo -22 > actions/NETDEV_CHANGEMTU/error
82 # ip link set eth0 mtu 1024
83 RTNETLINK answers: Invalid argument
84
85For more usage examples
86-----------------------
87There are tools/testing/selftests using the notifier error injection features
88for CPU and memory notifiers.
89
90 * tools/testing/selftests/cpu-hotplug/on-off-test.sh
91 * tools/testing/selftests/memory-hotplug/on-off-test.sh
92
93These scripts first do simple online and offline tests and then do fault
94injection tests if notifier error injection module is available.