From 02fff96a79775b7adc34eb599fc6b0476ccda520 Mon Sep 17 00:00:00 2001 From: Nikolay Aleksandrov Date: Sat, 28 Nov 2015 13:45:28 +0100 Subject: [PATCH] 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 +++++++++ lib/Kconfig.debug | 23 ++++++++ lib/Makefile | 1 + lib/netdev-notifier-error-inject.c | 54 +++++++++++++++++++ 4 files changed, 102 insertions(+) create mode 100644 lib/netdev-notifier-error-inject.c 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 diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 8c15b29d5adc..0d76ecce27bb 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1484,6 +1484,29 @@ config OF_RECONFIG_NOTIFIER_ERROR_INJECT If unsure, say N. +config NETDEV_NOTIFIER_ERROR_INJECT + tristate "Netdev notifier error injection module" + depends on NET && NOTIFIER_ERROR_INJECTION + help + This option provides the ability to inject artificial errors to + netdevice notifier chain callbacks. It is controlled through debugfs + interface /sys/kernel/debug/notifier-error-inject/netdev + + If the notifier call chain should be failed with some events + notified, write the error code to "actions//error". + + 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 + + To compile this code as a module, choose M here: the module will + be called netdev-notifier-error-inject. + + If unsure, say N. + config FAULT_INJECTION bool "Fault-injection framework" depends on DEBUG_KERNEL diff --git a/lib/Makefile b/lib/Makefile index 7f1de26613d2..180dd4d0dd41 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -120,6 +120,7 @@ obj-$(CONFIG_FAULT_INJECTION) += fault-inject.o obj-$(CONFIG_NOTIFIER_ERROR_INJECTION) += notifier-error-inject.o obj-$(CONFIG_CPU_NOTIFIER_ERROR_INJECT) += cpu-notifier-error-inject.o obj-$(CONFIG_PM_NOTIFIER_ERROR_INJECT) += pm-notifier-error-inject.o +obj-$(CONFIG_NETDEV_NOTIFIER_ERROR_INJECT) += netdev-notifier-error-inject.o obj-$(CONFIG_MEMORY_NOTIFIER_ERROR_INJECT) += memory-notifier-error-inject.o obj-$(CONFIG_OF_RECONFIG_NOTIFIER_ERROR_INJECT) += \ of-reconfig-notifier-error-inject.o diff --git a/lib/netdev-notifier-error-inject.c b/lib/netdev-notifier-error-inject.c new file mode 100644 index 000000000000..b2b856675d61 --- /dev/null +++ b/lib/netdev-notifier-error-inject.c @@ -0,0 +1,54 @@ +#include +#include +#include + +#include "notifier-error-inject.h" + +static int priority; +module_param(priority, int, 0); +MODULE_PARM_DESC(priority, "specify netdevice notifier priority"); + +static struct notifier_err_inject netdev_notifier_err_inject = { + .actions = { + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_REGISTER) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_CHANGEMTU) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_CHANGENAME) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_PRE_UP) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_PRE_TYPE_CHANGE) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_POST_INIT) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_PRECHANGEMTU) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_PRECHANGEUPPER) }, + {} + } +}; + +static struct dentry *dir; + +static int netdev_err_inject_init(void) +{ + int err; + + dir = notifier_err_inject_init("netdev", notifier_err_inject_dir, + &netdev_notifier_err_inject, priority); + if (IS_ERR(dir)) + return PTR_ERR(dir); + + err = register_netdevice_notifier(&netdev_notifier_err_inject.nb); + if (err) + debugfs_remove_recursive(dir); + + return err; +} + +static void netdev_err_inject_exit(void) +{ + unregister_netdevice_notifier(&netdev_notifier_err_inject.nb); + debugfs_remove_recursive(dir); +} + +module_init(netdev_err_inject_init); +module_exit(netdev_err_inject_exit); + +MODULE_DESCRIPTION("Netdevice notifier error injection module"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Nikolay Aleksandrov ");