linux-kernel - Re: [alsa-devel] [PATCH v2] ASoC: wm9713: fix regmap free path

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Date:	Sun, 21 Feb 2016 11:12:51 +0100
From:	Lars-Peter Clausen <lars@...afoo.de>
To:	Robert Jarzmik <robert.jarzmik@...e.fr>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>,
	Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>
Cc:	alsa-devel@...a-project.org, patches@...nsource.wolfsonmicro.com,
	linux-kernel@...r.kernel.org
Subject: Re: [alsa-devel] [PATCH v2] ASoC: wm9713: fix regmap free path

On 02/20/2016 08:44 PM, Robert Jarzmik wrote:
> In the conversion to regmap, I assumed that the 2 following functions
> was working symetrically:
>  - snd_soc_codec_init_regmap()
>  - snd_soc_codec_exit_regmap(codec)
> 
> As a mater of fact with the current code the regmap is freed twice
> because of the devm_() call:
> (mutex_lock) from (debugfs_remove_recursive+0x50/0x1d0)
> (debugfs_remove_recursive) from (regmap_debugfs_exit+0x1c/0xd4)
> (regmap_debugfs_exit) from (regmap_exit+0x28/0xc8)
> (regmap_exit) from (release_nodes+0x18c/0x204)
> (release_nodes) from (device_release+0x18/0x90)
> (device_release) from (kobject_release+0x90/0x1bc)
> (kobject_release) from (wm9713_soc_remove+0x1c/0x24)
> (wm9713_soc_remove) from (soc_remove_component+0x50/0x7c)
> (soc_remove_component) from (soc_remove_dai_links+0x118/0x228)
> (soc_remove_dai_links) from (snd_soc_register_card+0x4e4/0xdd4)
> (snd_soc_register_card) from (devm_snd_soc_register_card+0x34/0x70)
> 
> Fix this by removing the doubled regmap free.

The correct fix is to use the non devm variant of regmap_init_ac97() in this
case. Device managed functions should only be used from inside a struct
device probe function.

- Lars