[PATCH 4.19 010/110] ALSA: sb8: add a check for request_region

[Greg Kroah-Hartman]

[ Upstream commit dcd0feac9bab901d5739de51b3f69840851f8919 ]

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

Signed-off-by: Kangjie Lu <k...@umn.edu>
Signed-off-by: Takashi Iwai <ti...@suse.de>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 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 d77dcba276b5..1eb8b61a185b 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],
-- 
2.19.1