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    Subject[PATCH 1/3] ASoC: stm32: spdifrx: fix inconsistent lock state
    Date
    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>
    ---
    sound/soc/stm/stm32_spdifrx.c | 12 +++++++-----
    1 file changed, 7 insertions(+), 5 deletions(-)

    diff --git a/sound/soc/stm/stm32_spdifrx.c b/sound/soc/stm/stm32_spdifrx.c
    index 3fd28ee01675..9c6beb610c17 100644
    --- a/sound/soc/stm/stm32_spdifrx.c
    +++ b/sound/soc/stm/stm32_spdifrx.c
    @@ -320,6 +320,7 @@ static void stm32_spdifrx_dma_ctrl_stop(struct stm32_spdifrx_data *spdifrx)
    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;
    @@ -327,7 +328,7 @@ static int stm32_spdifrx_start_sync(struct stm32_spdifrx_data *spdifrx)
    if (ret)
    return ret;

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

    spdifrx->refcount++;

    @@ -362,7 +363,7 @@ static int stm32_spdifrx_start_sync(struct stm32_spdifrx_data *spdifrx)
    "Failed to start synchronization\n");
    }

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

    return ret;
    }
    @@ -370,11 +371,12 @@ static int stm32_spdifrx_start_sync(struct stm32_spdifrx_data *spdifrx)
    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;
    }

    @@ -393,7 +395,7 @@ static void stm32_spdifrx_stop(struct stm32_spdifrx_data *spdifrx)
    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,
    --
    2.17.1
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