diff options
| -rw-r--r-- | Documentation/fault-injection/notifier-error-inject.txt | 99 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 11 | ||||
| -rw-r--r-- | lib/Makefile | 1 | ||||
| -rw-r--r-- | lib/notifier-error-inject.c | 112 | ||||
| -rw-r--r-- | lib/notifier-error-inject.h | 24 |
5 files changed, 247 insertions, 0 deletions
diff --git a/Documentation/fault-injection/notifier-error-inject.txt b/Documentation/fault-injection/notifier-error-inject.txt new file mode 100644 index 0000000..c83526c --- /dev/null +++ b/Documentation/fault-injection/notifier-error-inject.txt @@ -0,0 +1,99 @@ +Notifier error injection +======================== + +Notifier error injection provides the ability to inject artifical 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. + + * CPU notifier + * PM notifier + * Memory hotplug notifier + * powerpc pSeries reconfig notifier + +CPU notifier error injection module +----------------------------------- +This feature can be used to test the error handling of the CPU notifiers by +injecting artifical errors to CPU notifier chain callbacks. + +If the notifier call chain should be failed with some events notified, write +the error code to debugfs interface +/sys/kernel/debug/notifier-error-inject/cpu/actions/<notifier event>/error + +Possible CPU notifier events to be failed are: + + * CPU_UP_PREPARE + * CPU_UP_PREPARE_FROZEN + * CPU_DOWN_PREPARE + * CPU_DOWN_PREPARE_FROZEN + +Example1: Inject CPU offline error (-1 == -EPERM) + + # cd /sys/kernel/debug/notifier-error-inject/cpu + # echo -1 > actions/CPU_DOWN_PREPARE/error + # echo 0 > /sys/devices/system/cpu/cpu1/online + bash: echo: write error: Operation not permitted + +Example2: inject CPU online error (-2 == -ENOENT) + + # echo -2 > actions/CPU_UP_PREPARE/error + # echo 1 > /sys/devices/system/cpu/cpu1/online + bash: echo: write error: No such file or directory + +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 + +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. diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 4a18650..bdee91d 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1084,6 +1084,17 @@ config LKDTM Documentation on how to use the module can be found in Documentation/fault-injection/provoke-crashes.txt +config NOTIFIER_ERROR_INJECTION + tristate "Notifier error injection" + depends on DEBUG_KERNEL + select DEBUG_FS + help + This option provides the ability to inject artifical errors to + specified notifier chain callbacks. It is useful to test the error + handling of notifier call chain failures. + + Say N if unsure. + config CPU_NOTIFIER_ERROR_INJECT tristate "CPU notifier error injection module" depends on HOTPLUG_CPU && DEBUG_KERNEL diff --git a/lib/Makefile b/lib/Makefile index df663cc..71acfa44 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -90,6 +90,7 @@ obj-$(CONFIG_AUDIT_GENERIC) += audit.o obj-$(CONFIG_SWIOTLB) += swiotlb.o obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o obj-$(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 lib-$(CONFIG_GENERIC_BUG) += bug.o diff --git a/lib/notifier-error-inject.c b/lib/notifier-error-inject.c new file mode 100644 index 0000000..44b92cb --- /dev/null +++ b/lib/notifier-error-inject.c @@ -0,0 +1,112 @@ +#include <linux/module.h> + +#include "notifier-error-inject.h" + +static int debugfs_errno_set(void *data, u64 val) +{ + *(int *)data = clamp_t(int, val, -MAX_ERRNO, 0); + return 0; +} + +static int debugfs_errno_get(void *data, u64 *val) +{ + *val = *(int *)data; + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(fops_errno, debugfs_errno_get, debugfs_errno_set, + "%lld\n"); + +static struct dentry *debugfs_create_errno(const char *name, mode_t mode, + struct dentry *parent, int *value) +{ + return debugfs_create_file(name, mode, parent, value, &fops_errno); +} + +static int notifier_err_inject_callback(struct notifier_block *nb, + unsigned long val, void *p) +{ + int err = 0; + struct notifier_err_inject *err_inject = + container_of(nb, struct notifier_err_inject, nb); + struct notifier_err_inject_action *action; + + for (action = err_inject->actions; action->name; action++) { + if (action->val == val) { + err = action->error; + break; + } + } + if (err) + pr_info("Injecting error (%d) to %s\n", err, action->name); + + return notifier_from_errno(err); +} + +struct dentry *notifier_err_inject_dir; +EXPORT_SYMBOL_GPL(notifier_err_inject_dir); + +struct dentry *notifier_err_inject_init(const char *name, struct dentry *parent, + struct notifier_err_inject *err_inject, int priority) +{ + struct notifier_err_inject_action *action; + mode_t mode = S_IFREG | S_IRUSR | S_IWUSR; + struct dentry *dir; + struct dentry *actions_dir; + + err_inject->nb.notifier_call = notifier_err_inject_callback; + err_inject->nb.priority = priority; + + dir = debugfs_create_dir(name, parent); + if (!dir) + return ERR_PTR(-ENOMEM); + + actions_dir = debugfs_create_dir("actions", dir); + if (!actions_dir) + goto fail; + + for (action = err_inject->actions; action->name; action++) { + struct dentry *action_dir; + + action_dir = debugfs_create_dir(action->name, actions_dir); + if (!action_dir) + goto fail; + + /* + * Create debugfs r/w file containing action->error. If + * notifier call chain is called with action->val, it will + * fail with the error code + */ + if (!debugfs_create_errno("error", mode, action_dir, + &action->error)) + goto fail; + } + return dir; +fail: + debugfs_remove_recursive(dir); + return ERR_PTR(-ENOMEM); +} +EXPORT_SYMBOL_GPL(notifier_err_inject_init); + +static int __init err_inject_init(void) +{ + notifier_err_inject_dir = + debugfs_create_dir("notifier-error-inject", NULL); + + if (!notifier_err_inject_dir) + return -ENOMEM; + + return 0; +} + +static void __exit err_inject_exit(void) +{ + debugfs_remove_recursive(notifier_err_inject_dir); +} + +module_init(err_inject_init); +module_exit(err_inject_exit); + +MODULE_DESCRIPTION("Notifier error injection module"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>"); diff --git a/lib/notifier-error-inject.h b/lib/notifier-error-inject.h new file mode 100644 index 0000000..99b3b6f --- /dev/null +++ b/lib/notifier-error-inject.h @@ -0,0 +1,24 @@ +#include <linux/atomic.h> +#include <linux/debugfs.h> +#include <linux/notifier.h> + +struct notifier_err_inject_action { + unsigned long val; + int error; + const char *name; +}; + +#define NOTIFIER_ERR_INJECT_ACTION(action) \ + .name = #action, .val = (action), + +struct notifier_err_inject { + struct notifier_block nb; + struct notifier_err_inject_action actions[]; + /* The last slot must be terminated with zero sentinel */ +}; + +extern struct dentry *notifier_err_inject_dir; + +extern struct dentry *notifier_err_inject_init(const char *name, + struct dentry *parent, struct notifier_err_inject *err_inject, + int priority); |
