From 8d438288145f19f253a82ca71290b44fce79e23f Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Mon, 30 Jul 2012 14:43:02 -0700 Subject: fault-injection: notifier error injection This patchset provides kernel modules that can be used to test the error handling of notifier call chain failures by injecting artifical errors to the following notifier chain callbacks. * CPU notifier * PM notifier * memory hotplug notifier * powerpc pSeries reconfig notifier Example: 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 The patchset also adds cpu and memory hotplug tests to tools/testing/selftests These tests first do simple online and offline test and then do fault injection tests if notifier error injection module is available. This patch: The 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. This adds common basic functions to define which type of events can be fail and to initialize the debugfs interface to control what error code should be returned and which event should be failed. Signed-off-by: Akinobu Mita Cc: Pavel Machek Cc: "Rafael J. Wysocki" Cc: Greg KH Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Dave Jones Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/Kconfig.debug | 11 +++++ lib/Makefile | 1 + lib/notifier-error-inject.c | 112 ++++++++++++++++++++++++++++++++++++++++++++ lib/notifier-error-inject.h | 24 ++++++++++ 4 files changed, 148 insertions(+) create mode 100644 lib/notifier-error-inject.c create mode 100644 lib/notifier-error-inject.h (limited to 'lib') diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 4a186508bf8..bdee91d50a5 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 df663cc05c7..71acfa4489f 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 00000000000..44b92cb6224 --- /dev/null +++ b/lib/notifier-error-inject.c @@ -0,0 +1,112 @@ +#include + +#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 "); diff --git a/lib/notifier-error-inject.h b/lib/notifier-error-inject.h new file mode 100644 index 00000000000..99b3b6fc470 --- /dev/null +++ b/lib/notifier-error-inject.h @@ -0,0 +1,24 @@ +#include +#include +#include + +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); -- cgit v1.2.3