Re: [PATCH 5/7] PM: PM notifier error injection

From: Rafael J. Wysocki
Date: Thu Jul 07 2011 - 17:14:11 EST


On Sunday, July 03, 2011, Akinobu Mita wrote:
> This provides the ability to inject artifical errors to PM notifier
> chain callbacks. It is controlled through debugfs interface under
> /sys/kernel/debug/pm-notifier-error-inject/
>
> Each of the files in the directory represents an event which can be
> failed and contains the error code. If the notifier call chain should
> be failed with some events notified, write the error code to the files.
>
> Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
> Cc: Pavel Machek <pavel@xxxxxx>
> Cc: "Rafael J. Wysocki" <rjw@xxxxxxx>
> Cc: linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx
> ---
> kernel/power/main.c | 30 ++++++++++++++++++++++++++++++
> lib/Kconfig.debug | 8 ++++++++
> 2 files changed, 38 insertions(+), 0 deletions(-)
>
> diff --git a/kernel/power/main.c b/kernel/power/main.c
> index 6c601f8..04b3774 100644
> --- a/kernel/power/main.c
> +++ b/kernel/power/main.c
> @@ -42,6 +42,36 @@ int pm_notifier_call_chain(unsigned long val)
> return notifier_to_errno(ret);
> }
>
> +#ifdef CONFIG_PM_NOTIFIER_ERROR_INJECTION
> +
> +static struct err_inject_notifier_block err_inject_pm_notifier = {
> + .actions = {
> + { ERR_INJECT_NOTIFIER_ACTION(PM_HIBERNATION_PREPARE) },
> + { ERR_INJECT_NOTIFIER_ACTION(PM_SUSPEND_PREPARE) },
> + { ERR_INJECT_NOTIFIER_ACTION(PM_RESTORE_PREPARE) },
> + {}

Why have you omitted the PM_POST_* actions?

> + }
> +};
> +
> +static int __init err_inject_pm_notifier_init(void)
> +{
> + int err;
> +
> + err = err_inject_notifier_block_init(&err_inject_pm_notifier,
> + "pm-notifier-error-inject", -1);
> + if (err)
> + return err;
> +
> + err = register_pm_notifier(&err_inject_pm_notifier.nb);
> + if (err)
> + err_inject_notifier_block_cleanup(&err_inject_pm_notifier);
> +
> + return err;
> +}
> +late_initcall(err_inject_pm_notifier_init);
> +
> +#endif /* CONFIG_PM_NOTIFIER_ERROR_INJECTION */
> +
> /* If set, devices may be suspended and resumed asynchronously. */
> int pm_async_enabled = 1;
>
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index d944b32..3ffb38b 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1043,6 +1043,14 @@ config CPU_NOTIFIER_ERROR_INJECTION
> # echo 0 > /sys/devices/system/cpu/cpu1/online
> bash: echo: write error: Operation not permitted
>
> +config PM_NOTIFIER_ERROR_INJECTION
> + bool "PM notifier error injection"
> + depends on PM_DEBUG && NOTIFIER_ERROR_INJECTION
> + help
> + This option provides the ability to inject artifical errors to
> + PM notifier chain callbacks. It is controlled through debugfs
> + interface under /sys/kernel/debug/pm-notifier-error-inject/

I'm not sure the help is necessary. I think it should be selected
automatically if both PM_DEBUG and NOTIFIER_ERROR_INJECTION are set.

> +
> config CPU_NOTIFIER_ERROR_INJECT
> tristate "CPU notifier error injection module"
> depends on HOTPLUG_CPU && DEBUG_KERNEL

Thanks,
Rafael

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