[PATCH 2/4] ASoC: SOF: amd: guard adata->sdw dereferences with NULL check in IRQ handler

[Vijendar Mukunda <Vijendar.Mukunda@amd.com>]

The ACP external IRQ handler is registered before sdw_amd_probe() assigns
adata->sdw, so a stray interrupt in the probe window could reach the
adata->sdw->pdev[i] dereference with adata->sdw still NULL.

The same window exists on the teardown side: after sdw_amd_exit() frees
the context but before adata->sdw is cleared by the caller.

Add NULL checks for adata->sdw in acp_irq_handler() before dereferencing
->pdev[0] and ->pdev[1], and in amd_sof_handle_acp70_sdw_wake_event() for
the same reason.  The interrupt-status register write that acknowledges the
IRQ is kept outside the guard so the hardware bit is always cleared
regardless of whether the SoundWire context is live.

Fixes: 96eb81851012 ("ASoC: SOF: amd: add interrupt handling for SoundWire manager devices")
Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@amd.com>
---
 sound/soc/sof/amd/acp.c | 32 ++++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/sound/soc/sof/amd/acp.c b/sound/soc/sof/amd/acp.c
index 86e2402b8ffd..623e016f38b8 100644
--- a/sound/soc/sof/amd/acp.c
+++ b/sound/soc/sof/amd/acp.c
@@ -478,16 +478,20 @@ static void amd_sof_handle_acp70_sdw_wake_event(struct acp_dev_data *adata)
 	struct amd_sdw_manager *amd_manager;
 
 	if (adata->acp70_sdw0_wake_event) {
-		amd_manager = dev_get_drvdata(&adata->sdw->pdev[0]->dev);
-		if (amd_manager)
-			pm_request_resume(amd_manager->dev);
+		if (adata->sdw) {
+			amd_manager = dev_get_drvdata(&adata->sdw->pdev[0]->dev);
+			if (amd_manager)
+				pm_request_resume(amd_manager->dev);
+		}
 		adata->acp70_sdw0_wake_event = 0;
 	}
 
 	if (adata->acp70_sdw1_wake_event) {
-		amd_manager = dev_get_drvdata(&adata->sdw->pdev[1]->dev);
-		if (amd_manager)
-			pm_request_resume(amd_manager->dev);
+		if (adata->sdw) {
+			amd_manager = dev_get_drvdata(&adata->sdw->pdev[1]->dev);
+			if (amd_manager)
+				pm_request_resume(amd_manager->dev);
+		}
 		adata->acp70_sdw1_wake_event = 0;
 	}
 }
@@ -579,10 +583,12 @@ static irqreturn_t acp_irq_handler(int irq, void *dev_id)
 
 	val = snd_sof_dsp_read(sdev, ACP_DSP_BAR, desc->ext_intr_stat);
 	if (val & ACP_SDW0_IRQ_MASK) {
-		amd_manager = dev_get_drvdata(&adata->sdw->pdev[0]->dev);
 		snd_sof_dsp_write(sdev, ACP_DSP_BAR, desc->ext_intr_stat, ACP_SDW0_IRQ_MASK);
-		if (amd_manager)
-			schedule_work(&amd_manager->amd_sdw_irq_thread);
+		if (adata->sdw) {
+			amd_manager = dev_get_drvdata(&adata->sdw->pdev[0]->dev);
+			if (amd_manager)
+				schedule_work(&amd_manager->amd_sdw_irq_thread);
+		}
 		irq_flag = 1;
 	}
 
@@ -608,11 +614,13 @@ static irqreturn_t acp_irq_handler(int irq, void *dev_id)
 	if (desc->ext_intr_stat1) {
 		val = snd_sof_dsp_read(sdev, ACP_DSP_BAR, desc->ext_intr_stat1);
 		if (val & ACP_SDW1_IRQ_MASK) {
-			amd_manager = dev_get_drvdata(&adata->sdw->pdev[1]->dev);
 			snd_sof_dsp_write(sdev, ACP_DSP_BAR, desc->ext_intr_stat1,
 					  ACP_SDW1_IRQ_MASK);
-			if (amd_manager)
-				schedule_work(&amd_manager->amd_sdw_irq_thread);
+			if (adata->sdw) {
+				amd_manager = dev_get_drvdata(&adata->sdw->pdev[1]->dev);
+				if (amd_manager)
+					schedule_work(&amd_manager->amd_sdw_irq_thread);
+			}
 			irq_flag = 1;
 		}
 		switch (adata->pci_rev) {
-- 
2.53.0