Re: [linux-pm] [PATCH 3.0-rc3] PM: free memory bitmaps if opening /dev/snapshot fails

Re: [linux-pm] [PATCH 3.0-rc3] PM: free memory bitmaps if opening /dev/snapshot fails

[Rafael J. Wysocki]

On Friday, June 17, 2011, Michal Kubecek wrote:
> From: Michal Kubecek <mkubecek@suse.cz>
> 
> When opening /dev/snapshot device, snapshot_open() creates memory
> bitmaps which are freed in snapshot_release(). But if any of the
> callbacks called by pm_notifier_call_chain() returns NOTIFY_BAD, open()
> fails, snapshot_release() is never called and bitmaps are not freed.
> Next attempt to open /dev/snapshot then triggers BUG_ON() check in
> create_basic_memory_bitmaps(). This happens e.g. when vmwatchdog module
> is active on s390x.
> 
> Signed-off-by: Michal Kubecek <mkubecek@suse.cz>

Thanks, I'm going to push your patch for 3.0 + stable.

Rafael


> --- 
> 
> diff --git a/kernel/power/user.c b/kernel/power/user.c
> index 7d02d33..42ddbc6 100644
> --- a/kernel/power/user.c
> +++ b/kernel/power/user.c
> @@ -113,8 +113,10 @@ static int snapshot_open(struct inode *inode, struct file *filp)
>  		if (error)
>  			pm_notifier_call_chain(PM_POST_RESTORE);
>  	}
> -	if (error)
> +	if (error) {
> +		free_basic_memory_bitmaps();
>  		atomic_inc(&snapshot_device_available);
> +	}
>  	data->frozen = 0;
>  	data->ready = 0;
>  	data->platform_support = 0;
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>