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authorNikolay Aleksandrov <nikolay@cumulusnetworks.com>2015-11-28 13:45:28 +0100
committerDavid S. Miller <davem@davemloft.net>2015-12-01 15:31:57 -0500
commit02fff96a79775b7adc34eb599fc6b0476ccda520 (patch)
treeb8b5ccf5a9c21f47ef78f563ff8c6c734567be64 /lib
parent27a70af3f4cf633a1b86c0ac7b426e2fe16ad2e5 (diff)
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>
Diffstat (limited to 'lib')
-rw-r--r--lib/Kconfig.debug23
-rw-r--r--lib/Makefile1
-rw-r--r--lib/netdev-notifier-error-inject.c54
3 files changed, 78 insertions, 0 deletions
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/<notifier event>/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 <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+
+#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 <razor@blackwall.org>");