linux-kernel - Re: [PATCH] regmap: debugfs: Fix a boot time crash with early regmap init

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Date:	Thu, 24 Oct 2013 15:03:07 +0300
From:	Tero Kristo <t-kristo@...com>
To:	Mark Brown <broonie@...nel.org>
CC:	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] regmap: debugfs: Fix a boot time crash with early regmap
 init

On 10/24/2013 12:18 PM, Mark Brown wrote:
> On Thu, Oct 24, 2013 at 12:07:48PM +0300, Tero Kristo wrote:
>
>> +	if (!regmap_debugfs_root) {
>> +		struct regmap_debugfs_node *node;
>> +		node = kzalloc(sizeof(*node), GFP_KERNEL);
>> +		if (!node)
>> +			return;
>> +		node->map = map;
>> +		node->name = name;
>> +		list_add(&node->link, &regmap_debugfs_early);
>> +		return;
>> +	}
>> +
>
> init is somewhat parallel so I'd be happier if we locked the list to
> make sure that we don't corrupt the list.

Ok, I added a mutex for protection (later registration might take some 
time so didn't want to use spinlock.)

> We also need something to handle removal of items from the list if the
> regmap is destroyed prior to the initcall running (for example in error
> handling cases), otherwise we could end up creating debugfs files
> pointing at devices that no longer exist.

Added cleanup for the list in the regmap_debugfs_exit() call. Sending v2 
shortly.

-Tero
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