* Re: [PATCH] ASoC: atmel_ssc_dai: Remove wrong spinlock usage
@ 2019-09-18 9:48 ` Alexandre Belloni
0 siblings, 0 replies; 9+ messages in thread
From: Alexandre Belloni @ 2019-09-18 9:48 UTC (permalink / raw)
To: Gregory CLEMENT
Cc: Codrin Ciubotariu, Liam Girdwood, Mark Brown, alsa-devel,
linux-kernel, Nicolas Ferre, Ludovic Desroches, linux-arm-kernel
On 18/09/2019 11:41:14+0200, Gregory CLEMENT wrote:
> A potential bug was reported in the email "[BUG] atmel_ssc_dai: a
> possible sleep-in-atomic bug in atmel_ssc_shutdown"[1]
>
> Indeed in the function atmel_ssc_shutdown() free_irq() was called in a
> critical section protected by spinlock.
>
> However this spinlock is only used in atmel_ssc_shutdown() and
> atmel_ssc_startup() functions. After further analysis, it occurred that
> the call to these function are already protected by mutex used on the
> calling functions.
>
> Then we can remove the spinlock which will fix this bug as a side
> effect. Thanks to this patch the following message disappears:
>
> "BUG: sleeping function called from invalid context at
> kernel/locking/mutex.c:909"
>
> [1]: https://www.spinics.net/lists/alsa-devel/msg71286.html
>
> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
> ---
> sound/soc/atmel/atmel_ssc_dai.c | 7 -------
> 1 file changed, 7 deletions(-)
>
> diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c
> index 6f89483ac88c..365957e86419 100644
> --- a/sound/soc/atmel/atmel_ssc_dai.c
> +++ b/sound/soc/atmel/atmel_ssc_dai.c
> @@ -116,19 +116,16 @@ static struct atmel_pcm_dma_params ssc_dma_params[NUM_SSC_DEVICES][2] = {
> static struct atmel_ssc_info ssc_info[NUM_SSC_DEVICES] = {
> {
> .name = "ssc0",
> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[0].lock),
This member is now unused and can be removed from the struct.
Once fixed, Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> .dir_mask = SSC_DIR_MASK_UNUSED,
> .initialized = 0,
> },
> {
> .name = "ssc1",
> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[1].lock),
> .dir_mask = SSC_DIR_MASK_UNUSED,
> .initialized = 0,
> },
> {
> .name = "ssc2",
> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[2].lock),
> .dir_mask = SSC_DIR_MASK_UNUSED,
> .initialized = 0,
> },
> @@ -317,13 +314,11 @@ static int atmel_ssc_startup(struct snd_pcm_substream *substream,
>
> snd_soc_dai_set_dma_data(dai, substream, dma_params);
>
> - spin_lock_irq(&ssc_p->lock);
> if (ssc_p->dir_mask & dir_mask) {
> spin_unlock_irq(&ssc_p->lock);
> return -EBUSY;
> }
> ssc_p->dir_mask |= dir_mask;
> - spin_unlock_irq(&ssc_p->lock);
>
> return 0;
> }
> @@ -355,7 +350,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
>
> dir_mask = 1 << dir;
>
> - spin_lock_irq(&ssc_p->lock);
> ssc_p->dir_mask &= ~dir_mask;
> if (!ssc_p->dir_mask) {
> if (ssc_p->initialized) {
> @@ -369,7 +363,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
> ssc_p->cmr_div = ssc_p->tcmr_period = ssc_p->rcmr_period = 0;
> ssc_p->forced_divider = 0;
> }
> - spin_unlock_irq(&ssc_p->lock);
>
> /* Shutdown the SSC clock. */
> pr_debug("atmel_ssc_dai: Stopping clock\n");
> --
> 2.23.0
>
--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH] ASoC: atmel_ssc_dai: Remove wrong spinlock usage
@ 2019-09-18 9:48 ` Alexandre Belloni
0 siblings, 0 replies; 9+ messages in thread
From: Alexandre Belloni @ 2019-09-18 9:48 UTC (permalink / raw)
To: Gregory CLEMENT
Cc: alsa-devel, linux-kernel, Liam Girdwood, Ludovic Desroches,
Mark Brown, Codrin Ciubotariu, linux-arm-kernel
On 18/09/2019 11:41:14+0200, Gregory CLEMENT wrote:
> A potential bug was reported in the email "[BUG] atmel_ssc_dai: a
> possible sleep-in-atomic bug in atmel_ssc_shutdown"[1]
>
> Indeed in the function atmel_ssc_shutdown() free_irq() was called in a
> critical section protected by spinlock.
>
> However this spinlock is only used in atmel_ssc_shutdown() and
> atmel_ssc_startup() functions. After further analysis, it occurred that
> the call to these function are already protected by mutex used on the
> calling functions.
>
> Then we can remove the spinlock which will fix this bug as a side
> effect. Thanks to this patch the following message disappears:
>
> "BUG: sleeping function called from invalid context at
> kernel/locking/mutex.c:909"
>
> [1]: https://www.spinics.net/lists/alsa-devel/msg71286.html
>
> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
> ---
> sound/soc/atmel/atmel_ssc_dai.c | 7 -------
> 1 file changed, 7 deletions(-)
>
> diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c
> index 6f89483ac88c..365957e86419 100644
> --- a/sound/soc/atmel/atmel_ssc_dai.c
> +++ b/sound/soc/atmel/atmel_ssc_dai.c
> @@ -116,19 +116,16 @@ static struct atmel_pcm_dma_params ssc_dma_params[NUM_SSC_DEVICES][2] = {
> static struct atmel_ssc_info ssc_info[NUM_SSC_DEVICES] = {
> {
> .name = "ssc0",
> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[0].lock),
This member is now unused and can be removed from the struct.
Once fixed, Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> .dir_mask = SSC_DIR_MASK_UNUSED,
> .initialized = 0,
> },
> {
> .name = "ssc1",
> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[1].lock),
> .dir_mask = SSC_DIR_MASK_UNUSED,
> .initialized = 0,
> },
> {
> .name = "ssc2",
> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[2].lock),
> .dir_mask = SSC_DIR_MASK_UNUSED,
> .initialized = 0,
> },
> @@ -317,13 +314,11 @@ static int atmel_ssc_startup(struct snd_pcm_substream *substream,
>
> snd_soc_dai_set_dma_data(dai, substream, dma_params);
>
> - spin_lock_irq(&ssc_p->lock);
> if (ssc_p->dir_mask & dir_mask) {
> spin_unlock_irq(&ssc_p->lock);
> return -EBUSY;
> }
> ssc_p->dir_mask |= dir_mask;
> - spin_unlock_irq(&ssc_p->lock);
>
> return 0;
> }
> @@ -355,7 +350,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
>
> dir_mask = 1 << dir;
>
> - spin_lock_irq(&ssc_p->lock);
> ssc_p->dir_mask &= ~dir_mask;
> if (!ssc_p->dir_mask) {
> if (ssc_p->initialized) {
> @@ -369,7 +363,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
> ssc_p->cmr_div = ssc_p->tcmr_period = ssc_p->rcmr_period = 0;
> ssc_p->forced_divider = 0;
> }
> - spin_unlock_irq(&ssc_p->lock);
>
> /* Shutdown the SSC clock. */
> pr_debug("atmel_ssc_dai: Stopping clock\n");
> --
> 2.23.0
>
--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [alsa-devel] [PATCH] ASoC: atmel_ssc_dai: Remove wrong spinlock usage
2019-09-18 9:48 ` Alexandre Belloni
(?)
@ 2019-09-18 9:59 ` Gregory CLEMENT
-1 siblings, 0 replies; 9+ messages in thread
From: Gregory CLEMENT @ 2019-09-18 9:59 UTC (permalink / raw)
To: Alexandre Belloni
Cc: alsa-devel, linux-kernel, Nicolas Ferre, Liam Girdwood,
Ludovic Desroches, Mark Brown, Codrin Ciubotariu,
linux-arm-kernel
Hi Alex,
> On 18/09/2019 11:41:14+0200, Gregory CLEMENT wrote:
>> A potential bug was reported in the email "[BUG] atmel_ssc_dai: a
>> possible sleep-in-atomic bug in atmel_ssc_shutdown"[1]
>>
>> Indeed in the function atmel_ssc_shutdown() free_irq() was called in a
>> critical section protected by spinlock.
>>
>> However this spinlock is only used in atmel_ssc_shutdown() and
>> atmel_ssc_startup() functions. After further analysis, it occurred that
>> the call to these function are already protected by mutex used on the
>> calling functions.
>>
>> Then we can remove the spinlock which will fix this bug as a side
>> effect. Thanks to this patch the following message disappears:
>>
>> "BUG: sleeping function called from invalid context at
>> kernel/locking/mutex.c:909"
>>
>> [1]: https://www.spinics.net/lists/alsa-devel/msg71286.html
>>
>> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
>> ---
>> sound/soc/atmel/atmel_ssc_dai.c | 7 -------
>> 1 file changed, 7 deletions(-)
>>
>> diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c
>> index 6f89483ac88c..365957e86419 100644
>> --- a/sound/soc/atmel/atmel_ssc_dai.c
>> +++ b/sound/soc/atmel/atmel_ssc_dai.c
>> @@ -116,19 +116,16 @@ static struct atmel_pcm_dma_params ssc_dma_params[NUM_SSC_DEVICES][2] = {
>> static struct atmel_ssc_info ssc_info[NUM_SSC_DEVICES] = {
>> {
>> .name = "ssc0",
>> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[0].lock),
>
> This member is now unused and can be removed from the struct.
>
> Once fixed, Reviewed-by: Alexandre Belloni
> <alexandre.belloni@bootlin.com>
Indeed I wanted to do this but finally forgot.
I am sending a v2.
Thanks,
Gregory
>
>> .dir_mask = SSC_DIR_MASK_UNUSED,
>> .initialized = 0,
>> },
>> {
>> .name = "ssc1",
>> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[1].lock),
>> .dir_mask = SSC_DIR_MASK_UNUSED,
>> .initialized = 0,
>> },
>> {
>> .name = "ssc2",
>> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[2].lock),
>> .dir_mask = SSC_DIR_MASK_UNUSED,
>> .initialized = 0,
>> },
>> @@ -317,13 +314,11 @@ static int atmel_ssc_startup(struct snd_pcm_substream *substream,
>>
>> snd_soc_dai_set_dma_data(dai, substream, dma_params);
>>
>> - spin_lock_irq(&ssc_p->lock);
>> if (ssc_p->dir_mask & dir_mask) {
>> spin_unlock_irq(&ssc_p->lock);
>> return -EBUSY;
>> }
>> ssc_p->dir_mask |= dir_mask;
>> - spin_unlock_irq(&ssc_p->lock);
>>
>> return 0;
>> }
>> @@ -355,7 +350,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
>>
>> dir_mask = 1 << dir;
>>
>> - spin_lock_irq(&ssc_p->lock);
>> ssc_p->dir_mask &= ~dir_mask;
>> if (!ssc_p->dir_mask) {
>> if (ssc_p->initialized) {
>> @@ -369,7 +363,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
>> ssc_p->cmr_div = ssc_p->tcmr_period = ssc_p->rcmr_period = 0;
>> ssc_p->forced_divider = 0;
>> }
>> - spin_unlock_irq(&ssc_p->lock);
>>
>> /* Shutdown the SSC clock. */
>> pr_debug("atmel_ssc_dai: Stopping clock\n");
>> --
>> 2.23.0
>>
>
> --
> Alexandre Belloni, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
--
Gregory Clement, Bootlin
Embedded Linux and Kernel engineering
http://bootlin.com
_______________________________________________
Alsa-devel mailing list
Alsa-devel@alsa-project.org
https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH] ASoC: atmel_ssc_dai: Remove wrong spinlock usage
@ 2019-09-18 9:59 ` Gregory CLEMENT
0 siblings, 0 replies; 9+ messages in thread
From: Gregory CLEMENT @ 2019-09-18 9:59 UTC (permalink / raw)
To: Alexandre Belloni
Cc: Codrin Ciubotariu, Liam Girdwood, Mark Brown, alsa-devel,
linux-kernel, Nicolas Ferre, Ludovic Desroches, linux-arm-kernel
Hi Alex,
> On 18/09/2019 11:41:14+0200, Gregory CLEMENT wrote:
>> A potential bug was reported in the email "[BUG] atmel_ssc_dai: a
>> possible sleep-in-atomic bug in atmel_ssc_shutdown"[1]
>>
>> Indeed in the function atmel_ssc_shutdown() free_irq() was called in a
>> critical section protected by spinlock.
>>
>> However this spinlock is only used in atmel_ssc_shutdown() and
>> atmel_ssc_startup() functions. After further analysis, it occurred that
>> the call to these function are already protected by mutex used on the
>> calling functions.
>>
>> Then we can remove the spinlock which will fix this bug as a side
>> effect. Thanks to this patch the following message disappears:
>>
>> "BUG: sleeping function called from invalid context at
>> kernel/locking/mutex.c:909"
>>
>> [1]: https://www.spinics.net/lists/alsa-devel/msg71286.html
>>
>> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
>> ---
>> sound/soc/atmel/atmel_ssc_dai.c | 7 -------
>> 1 file changed, 7 deletions(-)
>>
>> diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c
>> index 6f89483ac88c..365957e86419 100644
>> --- a/sound/soc/atmel/atmel_ssc_dai.c
>> +++ b/sound/soc/atmel/atmel_ssc_dai.c
>> @@ -116,19 +116,16 @@ static struct atmel_pcm_dma_params ssc_dma_params[NUM_SSC_DEVICES][2] = {
>> static struct atmel_ssc_info ssc_info[NUM_SSC_DEVICES] = {
>> {
>> .name = "ssc0",
>> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[0].lock),
>
> This member is now unused and can be removed from the struct.
>
> Once fixed, Reviewed-by: Alexandre Belloni
> <alexandre.belloni@bootlin.com>
Indeed I wanted to do this but finally forgot.
I am sending a v2.
Thanks,
Gregory
>
>> .dir_mask = SSC_DIR_MASK_UNUSED,
>> .initialized = 0,
>> },
>> {
>> .name = "ssc1",
>> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[1].lock),
>> .dir_mask = SSC_DIR_MASK_UNUSED,
>> .initialized = 0,
>> },
>> {
>> .name = "ssc2",
>> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[2].lock),
>> .dir_mask = SSC_DIR_MASK_UNUSED,
>> .initialized = 0,
>> },
>> @@ -317,13 +314,11 @@ static int atmel_ssc_startup(struct snd_pcm_substream *substream,
>>
>> snd_soc_dai_set_dma_data(dai, substream, dma_params);
>>
>> - spin_lock_irq(&ssc_p->lock);
>> if (ssc_p->dir_mask & dir_mask) {
>> spin_unlock_irq(&ssc_p->lock);
>> return -EBUSY;
>> }
>> ssc_p->dir_mask |= dir_mask;
>> - spin_unlock_irq(&ssc_p->lock);
>>
>> return 0;
>> }
>> @@ -355,7 +350,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
>>
>> dir_mask = 1 << dir;
>>
>> - spin_lock_irq(&ssc_p->lock);
>> ssc_p->dir_mask &= ~dir_mask;
>> if (!ssc_p->dir_mask) {
>> if (ssc_p->initialized) {
>> @@ -369,7 +363,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
>> ssc_p->cmr_div = ssc_p->tcmr_period = ssc_p->rcmr_period = 0;
>> ssc_p->forced_divider = 0;
>> }
>> - spin_unlock_irq(&ssc_p->lock);
>>
>> /* Shutdown the SSC clock. */
>> pr_debug("atmel_ssc_dai: Stopping clock\n");
>> --
>> 2.23.0
>>
>
> --
> Alexandre Belloni, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
--
Gregory Clement, Bootlin
Embedded Linux and Kernel engineering
http://bootlin.com
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH] ASoC: atmel_ssc_dai: Remove wrong spinlock usage
@ 2019-09-18 9:59 ` Gregory CLEMENT
0 siblings, 0 replies; 9+ messages in thread
From: Gregory CLEMENT @ 2019-09-18 9:59 UTC (permalink / raw)
To: Alexandre Belloni
Cc: alsa-devel, linux-kernel, Liam Girdwood, Ludovic Desroches,
Mark Brown, Codrin Ciubotariu, linux-arm-kernel
Hi Alex,
> On 18/09/2019 11:41:14+0200, Gregory CLEMENT wrote:
>> A potential bug was reported in the email "[BUG] atmel_ssc_dai: a
>> possible sleep-in-atomic bug in atmel_ssc_shutdown"[1]
>>
>> Indeed in the function atmel_ssc_shutdown() free_irq() was called in a
>> critical section protected by spinlock.
>>
>> However this spinlock is only used in atmel_ssc_shutdown() and
>> atmel_ssc_startup() functions. After further analysis, it occurred that
>> the call to these function are already protected by mutex used on the
>> calling functions.
>>
>> Then we can remove the spinlock which will fix this bug as a side
>> effect. Thanks to this patch the following message disappears:
>>
>> "BUG: sleeping function called from invalid context at
>> kernel/locking/mutex.c:909"
>>
>> [1]: https://www.spinics.net/lists/alsa-devel/msg71286.html
>>
>> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
>> ---
>> sound/soc/atmel/atmel_ssc_dai.c | 7 -------
>> 1 file changed, 7 deletions(-)
>>
>> diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c
>> index 6f89483ac88c..365957e86419 100644
>> --- a/sound/soc/atmel/atmel_ssc_dai.c
>> +++ b/sound/soc/atmel/atmel_ssc_dai.c
>> @@ -116,19 +116,16 @@ static struct atmel_pcm_dma_params ssc_dma_params[NUM_SSC_DEVICES][2] = {
>> static struct atmel_ssc_info ssc_info[NUM_SSC_DEVICES] = {
>> {
>> .name = "ssc0",
>> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[0].lock),
>
> This member is now unused and can be removed from the struct.
>
> Once fixed, Reviewed-by: Alexandre Belloni
> <alexandre.belloni@bootlin.com>
Indeed I wanted to do this but finally forgot.
I am sending a v2.
Thanks,
Gregory
>
>> .dir_mask = SSC_DIR_MASK_UNUSED,
>> .initialized = 0,
>> },
>> {
>> .name = "ssc1",
>> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[1].lock),
>> .dir_mask = SSC_DIR_MASK_UNUSED,
>> .initialized = 0,
>> },
>> {
>> .name = "ssc2",
>> - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[2].lock),
>> .dir_mask = SSC_DIR_MASK_UNUSED,
>> .initialized = 0,
>> },
>> @@ -317,13 +314,11 @@ static int atmel_ssc_startup(struct snd_pcm_substream *substream,
>>
>> snd_soc_dai_set_dma_data(dai, substream, dma_params);
>>
>> - spin_lock_irq(&ssc_p->lock);
>> if (ssc_p->dir_mask & dir_mask) {
>> spin_unlock_irq(&ssc_p->lock);
>> return -EBUSY;
>> }
>> ssc_p->dir_mask |= dir_mask;
>> - spin_unlock_irq(&ssc_p->lock);
>>
>> return 0;
>> }
>> @@ -355,7 +350,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
>>
>> dir_mask = 1 << dir;
>>
>> - spin_lock_irq(&ssc_p->lock);
>> ssc_p->dir_mask &= ~dir_mask;
>> if (!ssc_p->dir_mask) {
>> if (ssc_p->initialized) {
>> @@ -369,7 +363,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
>> ssc_p->cmr_div = ssc_p->tcmr_period = ssc_p->rcmr_period = 0;
>> ssc_p->forced_divider = 0;
>> }
>> - spin_unlock_irq(&ssc_p->lock);
>>
>> /* Shutdown the SSC clock. */
>> pr_debug("atmel_ssc_dai: Stopping clock\n");
>> --
>> 2.23.0
>>
>
> --
> Alexandre Belloni, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
--
Gregory Clement, Bootlin
Embedded Linux and Kernel engineering
http://bootlin.com
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 9+ messages in thread