projects / mirror_ubuntu-bionic-kernel.git / blame
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|---|---|---|
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1 | Notifier error injection |
| 2 | ======================== | |
| 3 | ||
| 4e79162a | 4 | Notifier error injection provides the ability to inject artificial errors to |
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5 | specified notifier chain callbacks. It is useful to test the error handling of |
| 6 | notifier call chain failures which is rarely executed. There are kernel | |
| 7 | modules that can be used to test the following notifiers. | |
| 8 | ||
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9 | * PM notifier |
| 10 | * Memory hotplug notifier | |
| 11 | * powerpc pSeries reconfig notifier | |
| 02fff96a | 12 | * Netdevice notifier |
| 8d438288 | 13 | |
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14 | PM notifier error injection module |
| 15 | ---------------------------------- | |
| 16 | This feature is controlled through debugfs interface | |
| 17 | /sys/kernel/debug/notifier-error-inject/pm/actions/<notifier event>/error | |
| 18 | ||
| 19 | Possible PM notifier events to be failed are: | |
| 20 | ||
| 21 | * PM_HIBERNATION_PREPARE | |
| 22 | * PM_SUSPEND_PREPARE | |
| 23 | * PM_RESTORE_PREPARE | |
| 24 | ||
| 25 | Example: 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 | ||
| 32 | Memory hotplug notifier error injection module | |
| 33 | ---------------------------------------------- | |
| 34 | This feature is controlled through debugfs interface | |
| 35 | /sys/kernel/debug/notifier-error-inject/memory/actions/<notifier event>/error | |
| 36 | ||
| 37 | Possible memory notifier events to be failed are: | |
| 38 | ||
| 39 | * MEM_GOING_ONLINE | |
| 40 | * MEM_GOING_OFFLINE | |
| 41 | ||
| 42 | Example: 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 | ||
| 49 | powerpc pSeries reconfig notifier error injection module | |
| 50 | -------------------------------------------------------- | |
| 51 | This feature is controlled through debugfs interface | |
| 52 | /sys/kernel/debug/notifier-error-inject/pSeries-reconfig/actions/<notifier event>/error | |
| 53 | ||
| 54 | Possible 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 | ||
| 02fff96a NA |
61 | Netdevice notifier error injection module |
| 62 | ---------------------------------------------- | |
| 63 | This feature is controlled through debugfs interface | |
| 64 | /sys/kernel/debug/notifier-error-inject/netdev/actions/<notifier event>/error | |
| 65 | ||
| 66 | Netdevice 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 | |
| c39d0454 | 76 | * NETDEV_CHANGEUPPER |
| 02fff96a NA |
77 | |
| 78 | Example: 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 | ||
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85 | For more usage examples |
| 86 | ----------------------- | |
| 87 | There are tools/testing/selftests using the notifier error injection features | |
| 88 | for 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 | ||
| 93 | These scripts first do simple online and offline tests and then do fault | |
| 94 | injection tests if notifier error injection module is available. |