[PATCH] sound: sb8: add a check for request_region

[Kangjie Lu]

In case request_region fails, the fix returns an error code to
avoid NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@xxxxxxx>
---
 sound/isa/sb/sb8.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sound/isa/sb/sb8.c b/sound/isa/sb/sb8.c
index aa2a83eb81a9..dc27a480c2d9 100644
--- a/sound/isa/sb/sb8.c
+++ b/sound/isa/sb/sb8.c
@@ -111,6 +111,10 @@ static int snd_sb8_probe(struct device *pdev, unsigned int dev)
 
 	/* block the 0x388 port to avoid PnP conflicts */
 	acard->fm_res = request_region(0x388, 4, "SoundBlaster FM");
+	if (!acard->fm_res) {
+		err = -EBUSY;
+		goto _err;
+	}
 
 	if (port[dev] != SNDRV_AUTO_PORT) {
 		if ((err = snd_sbdsp_create(card, port[dev], irq[dev],
-- 
2.17.1