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 <akinobu.mita@gmail.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: netdev <netdev@vger.kernel.org>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Nikolay Aleksandrov 2015-11-28 13:45:28 +01:00 committed by David S. Miller
parent 27a70af3f4
commit 02fff96a79
4 changed files with 102 additions and 0 deletions

View file

@ -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/<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
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