From 02fff96a79775b7adc34eb599fc6b0476ccda520 Mon Sep 17 00:00:00 2001 From: Nikolay Aleksandrov Date: Sat, 28 Nov 2015 13:45:28 +0100 Subject: net: add support for netdev notifier error injection This module allows to insert errors in some of netdevice's notifier events. All network drivers use these notifiers to signal various events and to check if they are allowed, e.g. PRECHANGEMTU and CHANGEMTU afterwards. Until recently I had to run failure tests by injecting a custom module, but now this infrastructure makes it trivial to test these failure paths. Some of the recent bugs I fixed were found using this module. Here's an example: $ cd /sys/kernel/debug/notifier-error-inject/netdev $ echo -22 > actions/NETDEV_CHANGEMTU/error $ ip link set eth0 mtu 1024 RTNETLINK answers: Invalid argument CC: Akinobu Mita CC: "David S. Miller" CC: netdev Signed-off-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- .../fault-injection/notifier-error-inject.txt | 24 ++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'Documentation/fault-injection') diff --git a/Documentation/fault-injection/notifier-error-inject.txt b/Documentation/fault-injection/notifier-error-inject.txt index 09adabef513f..71e638a4c497 100644 --- a/Documentation/fault-injection/notifier-error-inject.txt +++ b/Documentation/fault-injection/notifier-error-inject.txt @@ -10,6 +10,7 @@ modules that can be used to test the following notifiers. * PM notifier * Memory hotplug notifier * powerpc pSeries reconfig notifier + * Netdevice notifier CPU notifier error injection module ----------------------------------- @@ -87,6 +88,29 @@ Possible pSeries reconfig notifier events to be failed are: * 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//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 + +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 -- cgit v1.2.3-59-g8ed1b