[alsa-devel] [PATCH] ALSA: ASoC: Fix memory leaks for the CS4270 driver
timur at freescale.com
Thu Sep 4 17:54:28 CEST 2008
Takashi Iwai wrote:
> - In cs4270_remove(), cs4270_i2c_detach() is called after
> snd_soc_free_pcms(). snd_soc_free_pcms() invokes snd_card_free()
> inside, and this releases the all resources already, including the
> control elements. That is, you free an already-freed item.
I was wondering why so few drivers were calling snd_ctl_remove(). :-)
> Well, looking the code again, you create only one element, and if
> this fails, there is no other remaining element. Thus, there is
> nothing to free there.
True, but I intend on adding more controls in the future, so I want to code to
handle that automatically.
> - The way you look for a kcontrol is wrong although it may work in
> practice. A usual way is to remember the kctl and use it for
> removal, or find the kctl via snd_ctl_find_id(), not _numid().
It would be nice if snd_kcontrol_new had a snd_kcontrol *. I could use it to
store the pointer for later deallocation. Would you accept a patch to add that?
> - Your patch merged in the ALSA tree already would conflict with this
> patch. This is a mess, results in the whole rebase of git tree.
What, wait other patch? I based this patch on
git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6.git. It should
apply cleanly on that repo.
> So, I think the code in 2.6.27 tree can stay as is. There is no leak
> in the end. But, we can fix cs4270.c in the latest ALSA tree,
> e.g. add a missing remove callback to release codec->reg_cache.
I'm confused, because I thought I was fixing the latest ALSA tree.
Linux kernel developer at Freescale
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