From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx122.postini.com [74.125.245.122]) by kanga.kvack.org (Postfix) with SMTP id 71C426B02B8 for ; Sat, 23 Jun 2012 10:58:58 -0400 (EDT) Received: by dakp5 with SMTP id p5so4303058dak.14 for ; Sat, 23 Jun 2012 07:58:57 -0700 (PDT) From: Akinobu Mita Subject: [PATCH -v4 1/6] fault-injection: notifier error injection Date: Sat, 23 Jun 2012 23:58:17 +0900 Message-Id: <1340463502-15341-2-git-send-email-akinobu.mita@gmail.com> In-Reply-To: <1340463502-15341-1-git-send-email-akinobu.mita@gmail.com> References: <1340463502-15341-1-git-send-email-akinobu.mita@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org, akpm@linux-foundation.org Cc: Akinobu Mita , Pavel Machek , "Rafael J. Wysocki" , linux-pm@lists.linux-foundation.org, Greg KH , linux-mm@kvack.org, Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev@lists.ozlabs.org, Michael Ellerman 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: linux-pm@lists.linux-foundation.org Cc: Greg KH Cc: linux-mm@kvack.org Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: linuxppc-dev@lists.ozlabs.org Cc: Michael Ellerman --- * v4 - prefix all APIs with notifier_err_inject_* - rearrange debugfs interface (e.g. $DEBUGFS/cpu-notifier-error-inject/CPU_DOWN_PREPARE --> $DEBUGFS/notifier-error-inject/cpu/actions/CPU_DOWN_PREPARE/error) lib/Kconfig.debug | 11 +++++ lib/Makefile | 1 + lib/notifier-error-inject.c | 112 +++++++++++++++++++++++++++++++++++++++++++ lib/notifier-error-inject.h | 24 ++++++++++ 4 files changed, 148 insertions(+) create mode 100644 lib/notifier-error-inject.c create mode 100644 lib/notifier-error-inject.h diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index ff5bdee..c848758 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1084,6 +1084,17 @@ config LKDTM Documentation on how to use the module can be found in Documentation/fault-injection/provoke-crashes.txt +config NOTIFIER_ERROR_INJECTION + tristate "Notifier error injection" + depends on DEBUG_KERNEL + select DEBUG_FS + help + This option provides the ability to inject artifical errors to + specified notifier chain callbacks. It is useful to test the error + handling of notifier call chain failures. + + Say N if unsure. + config CPU_NOTIFIER_ERROR_INJECT tristate "CPU notifier error injection module" depends on HOTPLUG_CPU && DEBUG_KERNEL diff --git a/lib/Makefile b/lib/Makefile index 8c31a0c..23fba9e 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -90,6 +90,7 @@ obj-$(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 + +#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 0000000..99b3b6f --- /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); -- 1.7.10.2 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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