Re: sound/firewire/motu/motu-pcm.c:191 pcm_open() error: double unlocked 'motu->mutex' (orig line 179)
From: Takashi Sakamoto
Date: Sun Dec 08 2019 - 18:28:24 EST
Hi Dan,
On Sun, Dec 08, 2019 at 11:40:34AM +0300, Dan Carpenter wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head: 94e89b40235476a83a53a47b9ffb0cb91a4c335e
> commit: 3fd80b2003882b6a328caff9e6b3a14bed61f27c ALSA: firewire-motu: use the same size of period for PCM substream in AMDTP streams
>
> If you fix the issue, kindly add following tag
> Reported-by: kbuild test robot <lkp@xxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
>
> smatch warnings:
> sound/firewire/motu/motu-pcm.c:191 pcm_open() error: double unlocked 'motu->mutex' (orig line 179)
Indeed, it's a bug introduced in v5.5 kernel. I posted a patch to fix
this just now:
https://mailman.alsa-project.org/pipermail/alsa-devel/2019-December/159552.html
> # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3fd80b2003882b6a328caff9e6b3a14bed61f27c
> git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> git remote update linus
> git checkout 3fd80b2003882b6a328caff9e6b3a14bed61f27c
> vim +191 sound/firewire/motu/motu-pcm.c
>
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 133 static int pcm_open(struct snd_pcm_substream *substream)
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 134 {
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 135 struct snd_motu *motu = substream->private_data;
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 136 const struct snd_motu_protocol *const protocol = motu->spec->protocol;
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 137 struct amdtp_domain *d = &motu->domain;
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 138 enum snd_motu_clock_source src;
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 139 int err;
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 140
> 71c3797779d3cd Takashi Sakamoto 2017-03-22 141 err = snd_motu_stream_lock_try(motu);
> 71c3797779d3cd Takashi Sakamoto 2017-03-22 142 if (err < 0)
> 71c3797779d3cd Takashi Sakamoto 2017-03-22 143 return err;
> 71c3797779d3cd Takashi Sakamoto 2017-03-22 144
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 145 mutex_lock(&motu->mutex);
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 146
> 8b460c76bd1712 Takashi Sakamoto 2017-08-20 147 err = snd_motu_stream_cache_packet_formats(motu);
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 148 if (err < 0)
> 71c3797779d3cd Takashi Sakamoto 2017-03-22 149 goto err_locked;
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 150
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 151 err = init_hw_info(motu, substream);
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 152 if (err < 0)
> 71c3797779d3cd Takashi Sakamoto 2017-03-22 153 goto err_locked;
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 154
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 155 err = protocol->get_clock_source(motu, &src);
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 156 if (err < 0)
> 71c3797779d3cd Takashi Sakamoto 2017-03-22 157 goto err_locked;
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 158
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 159 // When source of clock is not internal or any stream is reserved for
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 160 // transmission of PCM frames, the available sampling rate is limited
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 161 // at current one.
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 162 if (src != SND_MOTU_CLOCK_SOURCE_INTERNAL ||
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 163 (motu->substreams_counter > 0 && d->events_per_period > 0)) {
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 164 unsigned int frames_per_period = d->events_per_period;
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 165 unsigned int rate;
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 166
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 167 err = protocol->get_clock_rate(motu, &rate);
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 168 if (err < 0)
> 71c3797779d3cd Takashi Sakamoto 2017-03-22 169 goto err_locked;
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 170
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 171 substream->runtime->hw.rate_min = rate;
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 172 substream->runtime->hw.rate_max = rate;
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 173
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 174 if (frames_per_period > 0) {
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 175 err = snd_pcm_hw_constraint_minmax(substream->runtime,
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 176 SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 177 frames_per_period, frames_per_period);
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 178 if (err < 0) {
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 @179 mutex_unlock(&motu->mutex);
> ^^^^^^^^^^^^^^^^^^^^^^^^^^
> Delete this.
>
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 180 goto err_locked;
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 181 }
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 182 }
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 183 }
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 184
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 185 snd_pcm_set_sync(substream);
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 186
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 187 mutex_unlock(&motu->mutex);
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 188
> 3fd80b2003882b Takashi Sakamoto 2019-10-07 189 return 0;
> 71c3797779d3cd Takashi Sakamoto 2017-03-22 190 err_locked:
> 71c3797779d3cd Takashi Sakamoto 2017-03-22 @191 mutex_unlock(&motu->mutex);
> 71c3797779d3cd Takashi Sakamoto 2017-03-22 192 snd_motu_stream_lock_release(motu);
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 193 return err;
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 194 }
> dd49b2d1f04af9 Takashi Sakamoto 2017-03-22 195
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx Intel Corporation
Thanks
Takashi Sakamoto