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From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Akinobu Mita <akinobu.mita@gmail.com>
Subject: Re: [PATCH -v4 3/6] PM: PM notifier error injection module
Date: Thu, 28 Jun 2012 23:45:17 +0200
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Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
        Pavel Machek <pavel@ucw.cz>, linux-pm@lists.linux-foundation.org
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On Saturday, June 23, 2012, 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/notifier-error-inject/pm
> 
> Each of the files in "error" 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.
> 
> If the notifier call chain should be failed with some events notified,
> write the error code to "actions/<notifier event>/error".
> 
> 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
> 
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> Cc: Pavel Machek <pavel@ucw.cz>
> Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
> Cc: linux-pm@lists.linux-foundation.org

OK, I have no objections.

Thanks,
Rafael


> ---
> * v4
> - update modules to follow new interface
> 
>  lib/Kconfig.debug              |   24 ++++++++++++++++++++
>  lib/Makefile                   |    1 +
>  lib/pm-notifier-error-inject.c |   49 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 74 insertions(+)
>  create mode 100644 lib/pm-notifier-error-inject.c
> 
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index be0c197..246cea6 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1119,6 +1119,30 @@ config CPU_NOTIFIER_ERROR_INJECT
>  
>  	  If unsure, say N.
>  
> +config PM_NOTIFIER_ERROR_INJECT
> +	tristate "PM notifier error injection module"
> +	depends on PM && NOTIFIER_ERROR_INJECTION
> +	default m if PM_DEBUG
> +	help
> +	  This option provides the ability to inject artifical errors to
> +	  PM notifier chain callbacks.  It is controlled through debugfs
> +	  interface /sys/kernel/debug/notifier-error-inject/pm
> +
> +	  If the notifier call chain should be failed with some events
> +	  notified, write the error code to "actions/<notifier event>/error".
> +
> +	  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
> +
> +	  To compile this code as a module, choose M here: the module will
> +	  be called pm-notifier-error-inject.
> +
> +	  If unsure, say N.
> +
>  config FAULT_INJECTION
>  	bool "Fault-injection framework"
>  	depends on DEBUG_KERNEL
> diff --git a/lib/Makefile b/lib/Makefile
> index 23fba9e..230a949 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -92,6 +92,7 @@ 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
> +obj-$(CONFIG_PM_NOTIFIER_ERROR_INJECT) += pm-notifier-error-inject.o
>  
>  lib-$(CONFIG_GENERIC_BUG) += bug.o
>  
> diff --git a/lib/pm-notifier-error-inject.c b/lib/pm-notifier-error-inject.c
> new file mode 100644
> index 0000000..c094b2d
> --- /dev/null
> +++ b/lib/pm-notifier-error-inject.c
> @@ -0,0 +1,49 @@
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/suspend.h>
> +
> +#include "notifier-error-inject.h"
> +
> +static int priority;
> +module_param(priority, int, 0);
> +MODULE_PARM_DESC(priority, "specify PM notifier priority");
> +
> +static struct notifier_err_inject pm_notifier_err_inject = {
> +	.actions = {
> +		{ NOTIFIER_ERR_INJECT_ACTION(PM_HIBERNATION_PREPARE) },
> +		{ NOTIFIER_ERR_INJECT_ACTION(PM_SUSPEND_PREPARE) },
> +		{ NOTIFIER_ERR_INJECT_ACTION(PM_RESTORE_PREPARE) },
> +		{}
> +	}
> +};
> +
> +static struct dentry *dir;
> +
> +static int err_inject_init(void)
> +{
> +	int err;
> +
> +	dir = notifier_err_inject_init("pm", notifier_err_inject_dir,
> +					&pm_notifier_err_inject, priority);
> +	if (IS_ERR(dir))
> +		return PTR_ERR(dir);
> +
> +	err = register_pm_notifier(&pm_notifier_err_inject.nb);
> +	if (err)
> +		debugfs_remove_recursive(dir);
> +
> +	return err;
> +}
> +
> +static void err_inject_exit(void)
> +{
> +	unregister_pm_notifier(&pm_notifier_err_inject.nb);
> +	debugfs_remove_recursive(dir);
> +}
> +
> +module_init(err_inject_init);
> +module_exit(err_inject_exit);
> +
> +MODULE_DESCRIPTION("PM notifier error injection module");
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
> 

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