From 83ee87a31dc43a5fd6dee3562c146033c3a4cb39 Mon Sep 17 00:00:00 2001
From: Mauro Carvalho Chehab <mchehab@infradead.org>
Date: Sat, 14 Jun 2008 09:41:18 -0300
Subject: V4L/DVB (8026): Avoids an OOPS if dev struct can't be successfully
recovered
On some alsa versions, it seems that snd_pcm_substream_chip(substream)
is returning a NULL pointer. This causes an OOPS, as reported by:
https://bugs.launchpad.net/ubuntu/+source/linux-ubuntu-modules-2.6.24/+bug/212271
https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/212960
This patch avoids the OOPS by not letting and open() succeed.
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
---
drivers/media/video/em28xx/em28xx-audio.c | 6 ++++++
1 file changed, 6 insertions(+)
(limited to 'drivers/media/video/em28xx')
diff --git a/drivers/media/video/em28xx/em28xx-audio.c b/drivers/media/video/em28xx/em28xx-audio.c
index 343dff0f8a0..3c006103c1e 100644
--- a/drivers/media/video/em28xx/em28xx-audio.c
+++ b/drivers/media/video/em28xx/em28xx-audio.c
@@ -268,6 +268,12 @@ static int snd_em28xx_capture_open(struct snd_pcm_substream *substream)
dprintk("opening device and trying to acquire exclusive lock\n");
+ if (!dev) {
+ printk(KERN_ERR "BUG: em28xx can't find device struct."
+ " Can't proceed with open\n");
+ return -ENODEV;
+ }
+
/* Sets volume, mute, etc */
dev->mute = 0;
--
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