linux-kernel - Re: [PATCH 1/3] power: validate wakeup source before activating it.

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Message-ID: <20150425201225.GB3008@amd>
Date:	Sat, 25 Apr 2015 22:12:25 +0200
From:	Pavel Machek <pavel@....cz>
To:	Jin Qian <jinqian@...roid.com>
Cc:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] power: validate wakeup source before activating it.

On Wed 2015-04-22 17:50:10, Jin Qian wrote:
> A rogue wakeup source not registered in wakeup_sources list is not visible
> from wakeup_sources_stats_show. Check if the wakeup source is registered
> properly by looking at the timer function.

How often does that happen?

Will people on your systems actually notice that pr_err()?
								Pavel

> Signed-off-by: Jin Qian <jinqian@...roid.com>
> ---
>  drivers/base/power/wakeup.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
> index 7726200..f24c622 100644
> --- a/drivers/base/power/wakeup.c
> +++ b/drivers/base/power/wakeup.c
> @@ -14,6 +14,7 @@
>  #include <linux/suspend.h>
>  #include <linux/seq_file.h>
>  #include <linux/debugfs.h>
> +#include <linux/types.h>
>  #include <trace/events/power.h>
>  
>  #include "power.h"
> @@ -351,6 +352,19 @@ int device_set_wakeup_enable(struct device *dev, bool enable)
>  }
>  EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
>  
> +/**
> + * validate_wakeup_source - validate the given wakeup source.
> + * @ws: Wakeup source to be validated.
> + */
> +static bool validate_wakeup_source(struct wakeup_source *ws)
> +{
> +	/*
> +	 * Use timer function to check if the given source is initialized
> +	 * by wakeup_source_add.
> +	 */
> +	return ws->timer.function == pm_wakeup_timer_fn;
> +}
> +
>  /*
>   * The functions below use the observation that each wakeup event starts a
>   * period in which the system should not be suspended.  The moment this period
> @@ -391,6 +405,11 @@ static void wakeup_source_activate(struct wakeup_source *ws)
>  {
>  	unsigned int cec;
>  
> +	if (!validate_wakeup_source(ws)) {
> +		pr_err("unregistered wakeup source: %s\n", ws->name);
> +		return;
> +	}
> +
>  	/*
>  	 * active wakeup source should bring the system
>  	 * out of PM_SUSPEND_FREEZE state

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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