Re: [RFC 0/2] McBSP and ASoC OMAP update patches for 2430 and 34xx

[Felipe Balbi <me@felipebalbi.com>]

On Mon, Aug 25, 2008 at 03:30:13PM -0700, Steve Sakoman wrote:
> > Hmm, so the crash is actually somewhere else. Could you disable debug
> > and get the NULL pointer dereference at the right point ?
> 
> The output is below.  The crash seems to occur at the substream
> pointer dereference in the second line of snd_pcm_info (in
> pcm_native.c):
> 
> 	struct snd_pcm *pcm = substream->pcm;

yeah, at that point substream was NULL. I'm trying to trace the function
call to see why substream is getting NULLed.

I think the following patch is anyway a good thing to apply:

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index c49b9d9..c7c15cf 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -92,10 +92,11 @@ static inline void snd_leave_user(mm_segment_t fs)
 int snd_pcm_info(struct snd_pcm_substream *substream, struct snd_pcm_info *info)
 {
        struct snd_pcm_runtime *runtime;
-       struct snd_pcm *pcm = substream->pcm;
+       struct snd_pcm *pcm;
        struct snd_pcm_str *pstr = substream->pstr;
 
        snd_assert(substream != NULL, return -ENXIO);
+       pcm = substream->pcm;
        memset(info, 0, sizeof(*info));
        info->card = pcm->card->number;
        info->device = pcm->device;

-- 
balbi