[PATCH -next] ALSA: n64: check return value after calling platform_get_resource()

[Yang Yingliang]

It will cause null-ptr-deref if platform_get_resource() returns NULL,
we need check the return value.

Signed-off-by: Yang Yingliang <yangyingliang at huawei.com>
---
 sound/mips/snd-n64.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sound/mips/snd-n64.c b/sound/mips/snd-n64.c
index e35e93157755..463a6fe589eb 100644
--- a/sound/mips/snd-n64.c
+++ b/sound/mips/snd-n64.c
@@ -338,6 +338,10 @@ static int __init n64audio_probe(struct platform_device *pdev)
 	strcpy(card->longname, "N64 Audio");
 
 	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!res) {
+		err = -EINVAL;
+		goto fail_dma_alloc;
+	}
 	if (devm_request_irq(&pdev->dev, res->start, n64audio_isr,
 				IRQF_SHARED, "N64 Audio", priv)) {
 		err = -EBUSY;
-- 
2.25.1