ALSA: sb8: add a check for request_region

[ Upstream commit dcd0feac9bab901d5739de51b3f69840851f8919 ]

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

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/sound/isa/sb/sb8.c b/sound/isa/sb/sb8.c
index d77dcba..1eb8b61 100644 (file)
--- 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],