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authorMauro Carvalho Chehab <mchehab+samsung@kernel.org>2019-06-12 14:52:44 -0300
committerJonathan Corbet <corbet@lwn.net>2019-06-14 14:21:07 -0600
commit10ffebbed5503b1830c7920ef528075785351be6 (patch)
tree41fb1ae1995364ef33da5f9661de39b03fab003f /Documentation/fault-injection/notifier-error-inject.rst
parentf0ba43774cea3fc14732bb9243ce7238ae8a3202 (diff)
docs: fault-injection: convert docs to ReST and rename to *.rst
The conversion is actually: - add blank lines and identation in order to identify paragraphs; - fix tables markups; - add some lists markups; - mark literal blocks; - adjust title markups. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Federico Vaga <federico.vaga@vaga.pv.it> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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+Notifier error injection
+========================
+
+Notifier error injection provides the ability to inject artificial errors to
+specified notifier chain callbacks. It is useful to test the error handling of
+notifier call chain failures which is rarely executed. There are kernel
+modules that can be used to test the following notifiers.
+
+ * PM notifier
+ * Memory hotplug notifier
+ * powerpc pSeries reconfig notifier
+ * Netdevice notifier
+
+PM notifier error injection module
+----------------------------------
+This feature is controlled through debugfs interface
+
+ /sys/kernel/debug/notifier-error-inject/pm/actions/<notifier event>/error
+
+Possible PM notifier events to be failed are:
+
+ * PM_HIBERNATION_PREPARE
+ * PM_SUSPEND_PREPARE
+ * PM_RESTORE_PREPARE
+
+Example: Inject PM suspend error (-12 = -ENOMEM)::
+
+ # cd /sys/kernel/debug/notifier-error-inject/pm/
+ # echo -12 > actions/PM_SUSPEND_PREPARE/error
+ # echo mem > /sys/power/state
+ bash: echo: write error: Cannot allocate memory
+
+Memory hotplug notifier error injection module
+----------------------------------------------
+This feature is controlled through debugfs interface
+
+ /sys/kernel/debug/notifier-error-inject/memory/actions/<notifier event>/error
+
+Possible memory notifier events to be failed are:
+
+ * MEM_GOING_ONLINE
+ * MEM_GOING_OFFLINE
+
+Example: Inject memory hotplug offline error (-12 == -ENOMEM)::
+
+ # cd /sys/kernel/debug/notifier-error-inject/memory
+ # echo -12 > actions/MEM_GOING_OFFLINE/error
+ # echo offline > /sys/devices/system/memory/memoryXXX/state
+ bash: echo: write error: Cannot allocate memory
+
+powerpc pSeries reconfig notifier error injection module
+--------------------------------------------------------
+This feature is controlled through debugfs interface
+
+ /sys/kernel/debug/notifier-error-inject/pSeries-reconfig/actions/<notifier event>/error
+
+Possible pSeries reconfig notifier events to be failed are:
+
+ * PSERIES_RECONFIG_ADD
+ * PSERIES_RECONFIG_REMOVE
+ * PSERIES_DRCONF_MEM_ADD
+ * PSERIES_DRCONF_MEM_REMOVE
+
+Netdevice notifier error injection module
+----------------------------------------------
+This feature is controlled through debugfs interface
+
+ /sys/kernel/debug/notifier-error-inject/netdev/actions/<notifier event>/error
+
+Netdevice notifier events which can be failed are:
+
+ * NETDEV_REGISTER
+ * NETDEV_CHANGEMTU
+ * NETDEV_CHANGENAME
+ * NETDEV_PRE_UP
+ * NETDEV_PRE_TYPE_CHANGE
+ * NETDEV_POST_INIT
+ * NETDEV_PRECHANGEMTU
+ * NETDEV_PRECHANGEUPPER
+ * NETDEV_CHANGEUPPER
+
+Example: Inject netdevice mtu change error (-22 == -EINVAL)::
+
+ # cd /sys/kernel/debug/notifier-error-inject/netdev
+ # echo -22 > actions/NETDEV_CHANGEMTU/error
+ # ip link set eth0 mtu 1024
+ RTNETLINK answers: Invalid argument
+
+For more usage examples
+-----------------------
+There are tools/testing/selftests using the notifier error injection features
+for CPU and memory notifiers.
+
+ * tools/testing/selftests/cpu-hotplug/on-off-test.sh
+ * tools/testing/selftests/memory-hotplug/on-off-test.sh
+
+These scripts first do simple online and offline tests and then do fault
+injection tests if notifier error injection module is available.