Fix gus_pcm dereference before NULL

Fix gus_pcm dereference before NULL

[Eugene Teo]

substream is dereferenced before checking for NULL.

Coverity bug #861

Signed-off-by: Eugene Teo <eugene.teo@eugeneteo.net>

--- linux-2.6/sound/isa/gus/gus_pcm.c~	2006-03-15 10:05:45.000000000 +0800
+++ linux-2.6/sound/isa/gus/gus_pcm.c	2006-03-16 09:51:43.000000000 +0800
@@ -103,8 +103,8 @@
 
 static void snd_gf1_pcm_trigger_up(struct snd_pcm_substream *substream)
 {
-	struct snd_pcm_runtime *runtime = substream->runtime;
-	struct gus_pcm_private *pcmp = runtime->private_data;
+	struct snd_pcm_runtime *runtime;
+	struct gus_pcm_private *pcmp;
 	struct snd_gus_card * gus = pcmp->gus;
 	unsigned long flags;
 	unsigned char voice_ctrl, ramp_ctrl;
@@ -114,8 +114,10 @@
 	unsigned char pan;
 	unsigned int voice;
 
-	if (substream == NULL)
+	if (substream == NULL || substream->runtime == NULL)
 		return;
+	runtime = substream->runtime;
+	pcmp = runtime->private_data;
 	spin_lock_irqsave(&pcmp->lock, flags);
 	if (pcmp->flags & SNDRV_GF1_PCM_PFLG_ACTIVE) {
 		spin_unlock_irqrestore(&pcmp->lock, flags);

-- 
1024D/A6D12F80 print D51D 2633 8DAC 04DB 7265  9BB8 5883 6DAA A6D1 2F80
main(i) { putchar(182623909 >> (i-1) * 5&31|!!(i<7)<<6) && main(++i); }

Re: Fix gus_pcm dereference before NULL

[Randy.Dunlap]

On Thu, 16 Mar 2006 10:00:07 +0800 Eugene Teo wrote:

> substream is dereferenced before checking for NULL.
> 
> Coverity bug #861
> 
> Signed-off-by: Eugene Teo <eugene.teo@eugeneteo.net>
> 
> --- linux-2.6/sound/isa/gus/gus_pcm.c~	2006-03-15 10:05:45.000000000 +0800
> +++ linux-2.6/sound/isa/gus/gus_pcm.c	2006-03-16 09:51:43.000000000 +0800
> @@ -103,8 +103,8 @@

BTW, please use "-p" diff option so that the "@@" sections
include function or struct names etc.  I.e., be nice to patch
readers/reviewers.  :)

---
~Randy

Re: Fix gus_pcm dereference before NULL

[Jan Engelhardt]

>
>BTW, please use "-p" diff option so that the "@@" sections
>include function or struct names etc.  I.e., be nice to patch
>readers/reviewers.  :)
>
Talking of diff flags, how about adding -d? Does not cost too much.


Jan Engelhardt
-- 

Re: Fix gus_pcm dereference before NULL

[Takashi Iwai]

At Thu, 16 Mar 2006 10:00:07 +0800,
Eugene Teo wrote:
> 
> substream is dereferenced before checking for NULL.

The NULL check of substream is simply superfluous.
It is guaranteed to receive non-NULL substream and
substream->runtime.


Takashi

> 
> Coverity bug #861
> 
> Signed-off-by: Eugene Teo <eugene.teo@eugeneteo.net>
> 
> --- linux-2.6/sound/isa/gus/gus_pcm.c~	2006-03-15 10:05:45.000000000 +0800
> +++ linux-2.6/sound/isa/gus/gus_pcm.c	2006-03-16 09:51:43.000000000 +0800
> @@ -103,8 +103,8 @@
>  
>  static void snd_gf1_pcm_trigger_up(struct snd_pcm_substream *substream)
>  {
> -	struct snd_pcm_runtime *runtime = substream->runtime;
> -	struct gus_pcm_private *pcmp = runtime->private_data;
> +	struct snd_pcm_runtime *runtime;
> +	struct gus_pcm_private *pcmp;
>  	struct snd_gus_card * gus = pcmp->gus;
>  	unsigned long flags;
>  	unsigned char voice_ctrl, ramp_ctrl;
> @@ -114,8 +114,10 @@
>  	unsigned char pan;
>  	unsigned int voice;
>  
> -	if (substream == NULL)
> +	if (substream == NULL || substream->runtime == NULL)
>  		return;
> +	runtime = substream->runtime;
> +	pcmp = runtime->private_data;
>  	spin_lock_irqsave(&pcmp->lock, flags);
>  	if (pcmp->flags & SNDRV_GF1_PCM_PFLG_ACTIVE) {
>  		spin_unlock_irqrestore(&pcmp->lock, flags);
> 
> -- 
> 1024D/A6D12F80 print D51D 2633 8DAC 04DB 7265  9BB8 5883 6DAA A6D1 2F80
> main(i) { putchar(182623909 >> (i-1) * 5&31|!!(i<7)<<6) && main(++i); }
> 
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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> 

Re: Fix gus_pcm dereference before NULL

[Eugene Teo]

<quote sender="Takashi Iwai">
> At Thu, 16 Mar 2006 10:00:07 +0800,
> Eugene Teo wrote:
> > 
> > substream is dereferenced before checking for NULL.
> 
> The NULL check of substream is simply superfluous.
> It is guaranteed to receive non-NULL substream and
> substream->runtime.
> > 
> > Coverity bug #861
> > 
> > Signed-off-by: Eugene Teo <eugene.teo@eugeneteo.net>

Resend.

Eugene

--
The NULL check of substream is simply superfluous. It is
guaranteed to receive non-NULL substream. Thanks Takashi.

Coverity bug #861

Signed-off-by: Eugene Teo <eugene.teo@eugeneteo.net>

--- linux-2.6/sound/isa/gus/gus_pcm.c~	2006-03-15 10:05:45.000000000 +0800
+++ linux-2.6/sound/isa/gus/gus_pcm.c	2006-03-16 19:50:45.000000000 +0800
@@ -114,8 +114,6 @@ static void snd_gf1_pcm_trigger_up(struc
 	unsigned char pan;
 	unsigned int voice;
 
-	if (substream == NULL)
-		return;
 	spin_lock_irqsave(&pcmp->lock, flags);
 	if (pcmp->flags & SNDRV_GF1_PCM_PFLG_ACTIVE) {
 		spin_unlock_irqrestore(&pcmp->lock, flags);

-- 
1024D/A6D12F80 print D51D 2633 8DAC 04DB 7265  9BB8 5883 6DAA A6D1 2F80
main(i) { putchar(182623909 >> (i-1) * 5&31|!!(i<7)<<6) && main(++i); }