[PATCH] sound: oss: ad1848: Fix returned errno code in ad1848_init()

[PATCH] sound: oss: ad1848: Fix returned errno code in ad1848_init()

[Luis de Bethencourt]

The driver is using -1 instead of the -ENOMEM defined macro to specify
that a buffer allocation failed. Since the error number is propagated,
the caller will get a -EPERM which is the wrong error condition.

Smatch tool warning:
ad1848_init() warn: returning -1 instead of -ENOMEM is sloppy

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
---
 sound/oss/ad1848.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/oss/ad1848.c b/sound/oss/ad1848.c
index 10c8de1..6b35656 100644
--- a/sound/oss/ad1848.c
+++ b/sound/oss/ad1848.c
@@ -1992,7 +1992,7 @@ int ad1848_init (char *name, struct resource *ports, int irq, int dma_playback,
 	portc = kmalloc(sizeof(ad1848_port_info), GFP_KERNEL);
 	if(portc==NULL) {
 		release_region(devc->base, 4);
-		return -1;
+		return -ENOMEM;
 	}
 
 	if ((my_dev = sound_install_audiodrv(AUDIO_DRIVER_VERSION,
-- 
2.5.3

Re: [PATCH] sound: oss: ad1848: Fix returned errno code in ad1848_init()

[Sudip Mukherjee]

On Tue, Sep 22, 2015 at 04:37:37PM +0100, Luis de Bethencourt wrote:
> The driver is using -1 instead of the -ENOMEM defined macro to specify
> that a buffer allocation failed. Since the error number is propagated,
> the caller will get a -EPERM which is the wrong error condition.
> 
> Smatch tool warning:
> ad1848_init() warn: returning -1 instead of -ENOMEM is sloppy
> 
> Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
> ---
>  sound/oss/ad1848.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/oss/ad1848.c b/sound/oss/ad1848.c
> index 10c8de1..6b35656 100644
> --- a/sound/oss/ad1848.c
> +++ b/sound/oss/ad1848.c
> @@ -1992,7 +1992,7 @@ int ad1848_init (char *name, struct resource *ports, int irq, int dma_playback,
>  	portc = kmalloc(sizeof(ad1848_port_info), GFP_KERNEL);
>  	if(portc==NULL) {
>  		release_region(devc->base, 4);
> -		return -1;
> +		return -ENOMEM;
 The return value of ad1848_init is stored in hw_config->slots[0].
And in sound/oss/pss.c hw_config->slots[0] is checked like: 
if (hw_config->slots[0] != -1)

So, you just changed the functionality of the driver.

regards
sudip

Re: [PATCH] sound: oss: ad1848: Fix returned errno code in ad1848_init()

[Luis de Bethencourt]

On 22/09/15 17:46, Sudip Mukherjee wrote:
> On Tue, Sep 22, 2015 at 04:37:37PM +0100, Luis de Bethencourt wrote:
>> The driver is using -1 instead of the -ENOMEM defined macro to specify
>> that a buffer allocation failed. Since the error number is propagated,
>> the caller will get a -EPERM which is the wrong error condition.
>>
>> Smatch tool warning:
>> ad1848_init() warn: returning -1 instead of -ENOMEM is sloppy
>>
>> Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
>> ---
>>  sound/oss/ad1848.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/sound/oss/ad1848.c b/sound/oss/ad1848.c
>> index 10c8de1..6b35656 100644
>> --- a/sound/oss/ad1848.c
>> +++ b/sound/oss/ad1848.c
>> @@ -1992,7 +1992,7 @@ int ad1848_init (char *name, struct resource *ports, int irq, int dma_playback,
>>  	portc = kmalloc(sizeof(ad1848_port_info), GFP_KERNEL);
>>  	if(portc==NULL) {
>>  		release_region(devc->base, 4);
>> -		return -1;
>> +		return -ENOMEM;
>  The return value of ad1848_init is stored in hw_config->slots[0].
> And in sound/oss/pss.c hw_config->slots[0] is checked like: 
> if (hw_config->slots[0] != -1)
> 
> So, you just changed the functionality of the driver.
> 
> regards
> sudip
> 

Hi Sudip,

True! I missed that.

This change will mean the block for 'if (hw_config->slots[0] != -1)' will
run and it shouldn't.

In ad1848.c:1998 sound_install_audiodrv() can return -ENOMEM as well, but this
is turned into -1 also. All errno codes are ignored in sound/oss/pss.c, not
worth it.

I'm withdrawing my patch. Sorry for this.

Is there any other way to silence the smatch warning?

Thanks for the review,
Luis

Re: [PATCH] sound: oss: ad1848: Fix returned errno code in ad1848_init()

[Sudip Mukherjee]

On Tue, Sep 22, 2015 at 08:11:13PM +0100, Luis de Bethencourt wrote:
> On 22/09/15 17:46, Sudip Mukherjee wrote:
> > On Tue, Sep 22, 2015 at 04:37:37PM +0100, Luis de Bethencourt wrote:
> 
<snip>
> Hi Sudip,
> 
> True! I missed that.
> 
> This change will mean the block for 'if (hw_config->slots[0] != -1)' will
> run and it shouldn't.
> 
> In ad1848.c:1998 sound_install_audiodrv() can return -ENOMEM as well, but this
> is turned into -1 also. All errno codes are ignored in sound/oss/pss.c, not
> worth it.
> 
> I'm withdrawing my patch. Sorry for this.
> 
> Is there any other way to silence the smatch warning?
Yes, ad1848_init() is only called from 3 places and everytime the return
is stored in hw_config->slots[0]. So change in all these 3 places and
then slots[0] is being checked in sound_unload_audiodev() and also in
sound/oss/pss.c, so you need to modify those checks also.
But these are all just from a quick grep, if you really want to change
then you need to see the driver carefully for other places that i might
have missed.

regards
sudip