[PATCH 4.14 22/71] ASoC: stm32: spdifrx: fix inconsistent lock state

Greg Kroah-Hartman
2020-01-16T23:36:28Z

From: Olivier Moysan <olivier.moysan@st.com>

commit 2859b1784031b5709446af8f6039c467f136e67d upstream.

In current spdifrx driver locks may be requested as follows:
- request lock on iec capture control, when starting synchronization.
- request lock in interrupt context, when spdifrx stop is called
from IRQ handler.

Take lock with IRQs disabled, to avoid the possible deadlock.

Lockdep report:
[ 74.278059] ================================
[ 74.282306] WARNING: inconsistent lock state
[ 74.290120] --------------------------------
...
[ 74.314373] CPU0
[ 74.314377] ----
[ 74.314381] lock(&(&spdifrx->lock)->rlock);
[ 74.314396] <Interrupt>
[ 74.314400] lock(&(&spdifrx->lock)->rlock);

Fixes: 03e4d5d56fa5 ("ASoC: stm32: Add SPDIFRX support")

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Link: https://lore.kernel.org/r/20191204154333.7152-2-olivier.moysan@st.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
sound/soc/stm/stm32_spdifrx.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

--- a/sound/soc/stm/stm32_spdifrx.c
+++ b/sound/soc/stm/stm32_spdifrx.c
@@ -313,6 +313,7 @@ static void stm32_spdifrx_dma_ctrl_stop(
static int stm32_spdifrx_start_sync(struct stm32_spdifrx_data *spdifrx)
{
int cr, cr_mask, imr, ret;
+ unsigned long flags;

/* Enable IRQs */
imr = SPDIFRX_IMR_IFEIE | SPDIFRX_IMR_SYNCDIE | SPDIFRX_IMR_PERRIE;
@@ -320,7 +321,7 @@ static int stm32_spdifrx_start_sync(stru
if (ret)
return ret;

- spin_lock(&spdifrx->lock);
+ spin_lock_irqsave(&spdifrx->lock, flags);

spdifrx->refcount++;

@@ -353,7 +354,7 @@ static int stm32_spdifrx_start_sync(stru
"Failed to start synchronization\n");
}

- spin_unlock(&spdifrx->lock);
+ spin_unlock_irqrestore(&spdifrx->lock, flags);

return ret;
}
@@ -361,11 +362,12 @@ static int stm32_spdifrx_start_sync(stru
static void stm32_spdifrx_stop(struct stm32_spdifrx_data *spdifrx)
{
int cr, cr_mask, reg;
+ unsigned long flags;

- spin_lock(&spdifrx->lock);
+ spin_lock_irqsave(&spdifrx->lock, flags);

if (--spdifrx->refcount) {
- spin_unlock(&spdifrx->lock);
+ spin_unlock_irqrestore(&spdifrx->lock, flags);
return;
}

@@ -384,7 +386,7 @@ static void stm32_spdifrx_stop(struct st
regmap_read(spdifrx->regmap, STM32_SPDIFRX_DR, &reg);
regmap_read(spdifrx->regmap, STM32_SPDIFRX_CSR, &reg);

- spin_unlock(&spdifrx->lock);
+ spin_unlock_irqrestore(&spdifrx->lock, flags);
}

static int stm32_spdifrx_dma_ctrl_register(struct device *dev,