[RFC PATCH 1/2] ASoC: sound: atmel_ac97c: Fix IRQ handler null pointer dereference

[Manish Baing]

In atmel_ac97c_probe(), request_irq() is called before ioremap().
If an interrupt fires immediately, the handler atmel_ac97c_interrupt()
will attempt to dereference chip->regs via ac97c_readl(), leading to
a null pointer dereference and kernel panic.

Move request_irq() to the end of the probe function, after memory
is mapped and clocks are enabled, ensuring the hardware is fully
ready before interrupts are serviced.

Running make W=1 returns no errors. I was unable to test the patch
because I do not have the hardware.The issue was flagged by the
Sashiko AI bot.

Link: https://sashiko.dev/#/patchset/20260530052812.115994-1-manishbaing2789@xxxxxxxxx?part=1
Reported-by: Sashiko AI <sashiko-bot@xxxxxxxxxx>
Signed-off-by: Manish Baing <manishbaing2789@xxxxxxxxx>
---
 sound/atmel/ac97c.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/sound/atmel/ac97c.c b/sound/atmel/ac97c.c
index df0a049192de..cd74395dd222 100644
--- a/sound/atmel/ac97c.c
+++ b/sound/atmel/ac97c.c
@@ -734,11 +734,6 @@ static int atmel_ac97c_probe(struct platform_device *pdev)
 
 	chip = get_chip(card);
 
-	retval = request_irq(irq, atmel_ac97c_interrupt, 0, "AC97C", chip);
-	if (retval) {
-		dev_dbg(&pdev->dev, "unable to request irq %d\n", irq);
-		goto err_request_irq;
-	}
 	chip->irq = irq;
 
 	spin_lock_init(&chip->lock);
@@ -786,6 +781,12 @@ static int atmel_ac97c_probe(struct platform_device *pdev)
 		goto err_ac97_bus;
 	}
 
+	retval = request_irq(irq, atmel_ac97c_interrupt, 0, "AC97C", chip);
+	if (retval) {
+		dev_dbg(&pdev->dev, "unable to request irq %d\n", irq);
+		goto err_request_irq;
+	}
+
 	retval = snd_card_register(card);
 	if (retval) {
 		dev_dbg(&pdev->dev, "could not register sound card\n");
-- 
2.43.0