From 83ee87a31dc43a5fd6dee3562c146033c3a4cb39 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Sat, 14 Jun 2008 09:41:18 -0300 Subject: [PATCH] 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 --- drivers/media/video/cx88/cx88-alsa.c | 6 ++++++ drivers/media/video/em28xx/em28xx-audio.c | 6 ++++++ drivers/media/video/saa7134/saa7134-alsa.c | 8 +++++++- 3 files changed, 19 insertions(+), 1 deletion(-) diff --git a/drivers/media/video/cx88/cx88-alsa.c b/drivers/media/video/cx88/cx88-alsa.c index e976fc6bef..80c8883e54 100644 --- a/drivers/media/video/cx88/cx88-alsa.c +++ b/drivers/media/video/cx88/cx88-alsa.c @@ -332,6 +332,12 @@ static int snd_cx88_pcm_open(struct snd_pcm_substream *substream) struct snd_pcm_runtime *runtime = substream->runtime; int err; + if (!chip) { + printk(KERN_ERR "BUG: cx88 can't find device struct." + " Can't proceed with open\n"); + return -ENODEV; + } + err = snd_pcm_hw_constraint_pow2(runtime, 0, SNDRV_PCM_HW_PARAM_PERIODS); if (err < 0) goto _error; diff --git a/drivers/media/video/em28xx/em28xx-audio.c b/drivers/media/video/em28xx/em28xx-audio.c index 343dff0f8a..3c006103c1 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; diff --git a/drivers/media/video/saa7134/saa7134-alsa.c b/drivers/media/video/saa7134/saa7134-alsa.c index ba3082422a..f118de6e36 100644 --- a/drivers/media/video/saa7134/saa7134-alsa.c +++ b/drivers/media/video/saa7134/saa7134-alsa.c @@ -613,9 +613,15 @@ static int snd_card_saa7134_capture_open(struct snd_pcm_substream * substream) struct snd_pcm_runtime *runtime = substream->runtime; snd_card_saa7134_pcm_t *pcm; snd_card_saa7134_t *saa7134 = snd_pcm_substream_chip(substream); - struct saa7134_dev *dev = saa7134->dev; + struct saa7134_dev *dev; int amux, err; + if (!saa7134) { + printk(KERN_ERR "BUG: saa7134 can't find device struct." + " Can't proceed with open\n"); + return -ENODEV; + } + dev = saa7134->dev; mutex_lock(&dev->dmasound.lock); dev->dmasound.read_count = 0; -- 2.39.5