From: Liam Girdwood <lrg@slimlogic.co.uk>
To: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Cc: alsa-devel@alsa-project.org, broonie@opensource.wolfsonmicro.com
Subject: Re: [PATCH] ASoC: core: Fix race in dapm_power_widgets
Date: Thu, 04 Nov 2010 09:51:02 +0000 [thread overview]
Message-ID: <1288864262.3277.10.camel@odin> (raw)
In-Reply-To: <1288858605-8388-1-git-send-email-peter.ujfalusi@nokia.com>
On Thu, 2010-11-04 at 10:16 +0200, Peter Ujfalusi wrote:
> dapm_power_widgets can be called from different context.
> When two calls are happening at the same time both will
> try to change states/lists. This can lead to kernel crash.
>
> A simple way to reproduce the problem:
>
> while [ "1" = "1" ] ; do
> amixer sset -Dhw:0 -q 'Mixer for loopback' on
> amixer sset -Dhw:0 -q 'Mixer for loopback' off
> done &
>
> while [ "1" = "1" ] ; do
> aplay -Dplughw:0 -fdat -d 3 /dev/urandom
> echo "Playback finished"
> sleep 6
> done &
>
> Add new card level mutex (dpw_mutex) to protect the
> dapm_power_widgets from race.
> The exisiting card->mutex can not be used for this purpose,
> since it has been taken in probe time in the
> snd_soc_instantiate_card function. Through probe calls from
> this function eventually dapm_power_widgets will be called,
> which will lead to dead lock.
>
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
--
Freelance Developer, SlimLogic Ltd
ASoC and Voltage Regulator Maintainer.
http://www.slimlogic.co.uk
next prev parent reply other threads:[~2010-11-04 9:51 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-04 8:16 [PATCH] ASoC: core: Fix race in dapm_power_widgets Peter Ujfalusi
2010-11-04 9:51 ` Liam Girdwood [this message]
2010-11-04 13:43 ` Mark Brown
2010-11-04 14:18 ` Peter Ujfalusi
2010-11-04 18:08 ` Mark Brown
2010-11-05 7:53 ` Peter Ujfalusi
2010-11-05 14:38 ` Mark Brown
2010-11-06 11:00 ` Liam Girdwood
2010-11-06 15:10 ` Mark Brown
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1288864262.3277.10.camel@odin \
--to=lrg@slimlogic.co.uk \
--cc=alsa-devel@alsa-project.org \
--cc=broonie@opensource.wolfsonmicro.com \
--cc=peter.ujfalusi@nokia.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).