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From:   Mark Brown <broonie@kernel.org>
To:     Olivier Moysan <olivier.moysan@st.com>
Cc:     alexandre.torgue@st.com, alsa-devel@alsa-project.org,
        broonie@kernel.org, lgirdwood@gmail.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com,
        Mark Brown <broonie@kernel.org>, mcoquelin.stm32@gmail.com,
        olivier.moysan@st.com, perex@perex.cz, tiwai@suse.com
Subject: Applied "ASoC: stm32: spdifrx: fix race condition in irq handler" to the asoc tree
In-Reply-To:  <20191204154333.7152-3-olivier.moysan@st.com>
Message-Id:  <applied-20191204154333.7152-3-olivier.moysan@st.com>
Date:   Wed, 25 Dec 2019 00:09:05 +0000 (GMT)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The patch

   ASoC: stm32: spdifrx: fix race condition in irq handler

has been applied to the asoc tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

From 86e1956af4c863d653136fd6e5694adf2054dbaa Mon Sep 17 00:00:00 2001
From: Olivier Moysan <olivier.moysan@st.com>
Date: Wed, 4 Dec 2019 16:43:32 +0100
Subject: [PATCH] ASoC: stm32: spdifrx: fix race condition in irq handler

When snd_pcm_stop() is called in interrupt routine,
substream context may have already been released.
Add protection on substream context.

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

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Link: https://lore.kernel.org/r/20191204154333.7152-3-olivier.moysan@st.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 sound/soc/stm/stm32_spdifrx.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/sound/soc/stm/stm32_spdifrx.c b/sound/soc/stm/stm32_spdifrx.c
index 9c6beb610c17..3cb8e6db3eeb 100644
--- a/sound/soc/stm/stm32_spdifrx.c
+++ b/sound/soc/stm/stm32_spdifrx.c
@@ -220,6 +220,7 @@
  * @slave_config: dma slave channel runtime config pointer
  * @phys_addr: SPDIFRX registers physical base address
  * @lock: synchronization enabling lock
+ * @irq_lock: prevent race condition with IRQ on stream state
  * @cs: channel status buffer
  * @ub: user data buffer
  * @irq: SPDIFRX interrupt line
@@ -240,6 +241,7 @@ struct stm32_spdifrx_data {
 	struct dma_slave_config slave_config;
 	dma_addr_t phys_addr;
 	spinlock_t lock;  /* Sync enabling lock */
+	spinlock_t irq_lock; /* Prevent race condition on stream state */
 	unsigned char cs[SPDIFRX_CS_BYTES_NB];
 	unsigned char ub[SPDIFRX_UB_BYTES_NB];
 	int irq;
@@ -667,7 +669,6 @@ static const struct regmap_config stm32_h7_spdifrx_regmap_conf = {
 static irqreturn_t stm32_spdifrx_isr(int irq, void *devid)
 {
 	struct stm32_spdifrx_data *spdifrx = (struct stm32_spdifrx_data *)devid;
-	struct snd_pcm_substream *substream = spdifrx->substream;
 	struct platform_device *pdev = spdifrx->pdev;
 	unsigned int cr, mask, sr, imr;
 	unsigned int flags, sync_state;
@@ -747,14 +748,19 @@ static irqreturn_t stm32_spdifrx_isr(int irq, void *devid)
 			return IRQ_HANDLED;
 		}
 
-		if (substream)
-			snd_pcm_stop(substream, SNDRV_PCM_STATE_DISCONNECTED);
+		spin_lock(&spdifrx->irq_lock);
+		if (spdifrx->substream)
+			snd_pcm_stop(spdifrx->substream,
+				     SNDRV_PCM_STATE_DISCONNECTED);
+		spin_unlock(&spdifrx->irq_lock);
 
 		return IRQ_HANDLED;
 	}
 
-	if (err_xrun && substream)
-		snd_pcm_stop_xrun(substream);
+	spin_lock(&spdifrx->irq_lock);
+	if (err_xrun && spdifrx->substream)
+		snd_pcm_stop_xrun(spdifrx->substream);
+	spin_unlock(&spdifrx->irq_lock);
 
 	return IRQ_HANDLED;
 }
@@ -763,9 +769,12 @@ static int stm32_spdifrx_startup(struct snd_pcm_substream *substream,
 				 struct snd_soc_dai *cpu_dai)
 {
 	struct stm32_spdifrx_data *spdifrx = snd_soc_dai_get_drvdata(cpu_dai);
+	unsigned long flags;
 	int ret;
 
+	spin_lock_irqsave(&spdifrx->irq_lock, flags);
 	spdifrx->substream = substream;
+	spin_unlock_irqrestore(&spdifrx->irq_lock, flags);
 
 	ret = clk_prepare_enable(spdifrx->kclk);
 	if (ret)
@@ -841,8 +850,12 @@ static void stm32_spdifrx_shutdown(struct snd_pcm_substream *substream,
 				   struct snd_soc_dai *cpu_dai)
 {
 	struct stm32_spdifrx_data *spdifrx = snd_soc_dai_get_drvdata(cpu_dai);
+	unsigned long flags;
 
+	spin_lock_irqsave(&spdifrx->irq_lock, flags);
 	spdifrx->substream = NULL;
+	spin_unlock_irqrestore(&spdifrx->irq_lock, flags);
+
 	clk_disable_unprepare(spdifrx->kclk);
 }
 
@@ -946,6 +959,7 @@ static int stm32_spdifrx_probe(struct platform_device *pdev)
 	spdifrx->pdev = pdev;
 	init_completion(&spdifrx->cs_completion);
 	spin_lock_init(&spdifrx->lock);
+	spin_lock_init(&spdifrx->irq_lock);
 
 	platform_set_drvdata(pdev, spdifrx);
 
-- 
2.20.1