From f5a9f52e2c5654c3d212dbf7e7a169c60876691a Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Mon, 30 Jul 2012 14:43:03 -0700 Subject: [PATCH] cpu: rewrite cpu-notifier-error-inject module Rewrite existing cpu-notifier-error-inject module to use debugfs based new framework. This change removes cpu_up_prepare_error and cpu_down_prepare_error module parameters which were used to specify error code to be injected. We could keep these module parameters for backward compatibility by module_param_cb but it seems overkill for this module. This provides the ability to inject artifical errors to CPU notifier chain callbacks. It is controlled through debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu If the notifier call chain should be failed with some events notified, write the error code to "actions//error". 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) # cd /sys/kernel/debug/notifier-error-inject/cpu # echo -2 > actions/CPU_UP_PREPARE/error # echo 1 > /sys/devices/system/cpu/cpu1/online bash: echo: write error: No such file or directory 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 | 16 +++++++-- lib/cpu-notifier-error-inject.c | 63 +++++++++++++-------------------- 2 files changed, 39 insertions(+), 40 deletions(-) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index bdee91d50a5b..20341480bb54 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1097,10 +1097,22 @@ config NOTIFIER_ERROR_INJECTION config CPU_NOTIFIER_ERROR_INJECT tristate "CPU notifier error injection module" - depends on HOTPLUG_CPU && DEBUG_KERNEL + depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION help This option provides a kernel module that can be used to test - the error handling of the cpu notifiers + the error handling of the cpu notifiers by injecting artifical + errors to CPU notifier chain callbacks. It is controlled through + debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu + + If the notifier call chain should be failed with some events + notified, write the error code to "actions//error". + + 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 To compile this code as a module, choose M here: the module will be called cpu-notifier-error-inject. diff --git a/lib/cpu-notifier-error-inject.c b/lib/cpu-notifier-error-inject.c index 4dc20321b0d5..707ca24f7b18 100644 --- a/lib/cpu-notifier-error-inject.c +++ b/lib/cpu-notifier-error-inject.c @@ -1,58 +1,45 @@ #include -#include #include -#include +#include -static int priority; -static int cpu_up_prepare_error; -static int cpu_down_prepare_error; +#include "notifier-error-inject.h" +static int priority; module_param(priority, int, 0); MODULE_PARM_DESC(priority, "specify cpu notifier priority"); -module_param(cpu_up_prepare_error, int, 0644); -MODULE_PARM_DESC(cpu_up_prepare_error, - "specify error code to inject CPU_UP_PREPARE action"); - -module_param(cpu_down_prepare_error, int, 0644); -MODULE_PARM_DESC(cpu_down_prepare_error, - "specify error code to inject CPU_DOWN_PREPARE action"); - -static int err_inject_cpu_callback(struct notifier_block *nfb, - unsigned long action, void *hcpu) -{ - int err = 0; - - switch (action) { - case CPU_UP_PREPARE: - case CPU_UP_PREPARE_FROZEN: - err = cpu_up_prepare_error; - break; - case CPU_DOWN_PREPARE: - case CPU_DOWN_PREPARE_FROZEN: - err = cpu_down_prepare_error; - break; +static struct notifier_err_inject cpu_notifier_err_inject = { + .actions = { + { NOTIFIER_ERR_INJECT_ACTION(CPU_UP_PREPARE) }, + { NOTIFIER_ERR_INJECT_ACTION(CPU_UP_PREPARE_FROZEN) }, + { NOTIFIER_ERR_INJECT_ACTION(CPU_DOWN_PREPARE) }, + { NOTIFIER_ERR_INJECT_ACTION(CPU_DOWN_PREPARE_FROZEN) }, + {} } - if (err) - printk(KERN_INFO "Injecting error (%d) at cpu notifier\n", err); - - return notifier_from_errno(err); -} - -static struct notifier_block err_inject_cpu_notifier = { - .notifier_call = err_inject_cpu_callback, }; +static struct dentry *dir; + static int err_inject_init(void) { - err_inject_cpu_notifier.priority = priority; + int err; + + dir = notifier_err_inject_init("cpu", notifier_err_inject_dir, + &cpu_notifier_err_inject, priority); + if (IS_ERR(dir)) + return PTR_ERR(dir); + + err = register_hotcpu_notifier(&cpu_notifier_err_inject.nb); + if (err) + debugfs_remove_recursive(dir); - return register_hotcpu_notifier(&err_inject_cpu_notifier); + return err; } static void err_inject_exit(void) { - unregister_hotcpu_notifier(&err_inject_cpu_notifier); + unregister_hotcpu_notifier(&cpu_notifier_err_inject.nb); + debugfs_remove_recursive(dir); } module_init(err_inject_init); -- 2.20.1