ALSA: cs4236: fix return check from call to pnp_port_start
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Message ID 20181010141542.16100-1-colin.king@canonical.com
State New
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Series
  • ALSA: cs4236: fix return check from call to pnp_port_start
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Commit Message

Colin King Oct. 10, 2018, 2:15 p.m. UTC
From: Colin Ian King <colin.king@canonical.com>

Currently the return from pnp_port_start is being checked for validity
by checking if it is greater or equal to zero, however, the return
is unsigned and hence this check is always true.  An 0 return from
pnp_port_start is actually an error, so fix the check by checking
for validity when it is non-zero.

Detected by CoverityScan, CID#1468334 ("Unsigned compared to 0")

Fixes: a9824c868a2c ("[ALSA] Add CS4232 PnP BIOS support")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 sound/isa/cs423x/cs4236.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Takashi Iwai Oct. 11, 2018, 3:42 p.m. UTC | #1
On Wed, 10 Oct 2018 16:15:42 +0200,
Colin King wrote:
> 
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently the return from pnp_port_start is being checked for validity
> by checking if it is greater or equal to zero, however, the return
> is unsigned and hence this check is always true.  An 0 return from
> pnp_port_start is actually an error, so fix the check by checking
> for validity when it is non-zero.

I guess you're confused between mpu_port[] and mpu_irq[]?
The check "mpu_irq[] >= 0" here is to see the module parameter value
from user.


thanks,

Takashi

> Detected by CoverityScan, CID#1468334 ("Unsigned compared to 0")
> 
> Fixes: a9824c868a2c ("[ALSA] Add CS4232 PnP BIOS support")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  sound/isa/cs423x/cs4236.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/isa/cs423x/cs4236.c b/sound/isa/cs423x/cs4236.c
> index 70559e59d18f..2211c39d2c18 100644
> --- a/sound/isa/cs423x/cs4236.c
> +++ b/sound/isa/cs423x/cs4236.c
> @@ -292,7 +292,7 @@ static int snd_cs423x_pnp_init_mpu(int dev, struct pnp_dev *pdev)
>  		mpu_irq[dev] = SNDRV_AUTO_IRQ;
>  	} else {
>  		mpu_port[dev] = pnp_port_start(pdev, 0);
> -		if (mpu_irq[dev] >= 0 &&
> +		if (!mpu_irq[dev] &&
>  		    pnp_irq_valid(pdev, 0) && pnp_irq(pdev, 0) >= 0) {
>  			mpu_irq[dev] = pnp_irq(pdev, 0);
>  		} else {
> -- 
> 2.17.1
> 
>
Colin King Oct. 11, 2018, 3:47 p.m. UTC | #2
On 11/10/18 16:42, Takashi Iwai wrote:
> On Wed, 10 Oct 2018 16:15:42 +0200,
> Colin King wrote:
>>
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> Currently the return from pnp_port_start is being checked for validity
>> by checking if it is greater or equal to zero, however, the return
>> is unsigned and hence this check is always true.  An 0 return from
>> pnp_port_start is actually an error, so fix the check by checking
>> for validity when it is non-zero.
> 
> I guess you're confused between mpu_port[] and mpu_irq[]?
> The check "mpu_irq[] >= 0" here is to see the module parameter value
> from user.

Yep, you are quite correct. I overlooked this. My bad.
> 
> 
> thanks,
> 
> Takashi
> 
>> Detected by CoverityScan, CID#1468334 ("Unsigned compared to 0")
>>
>> Fixes: a9824c868a2c ("[ALSA] Add CS4232 PnP BIOS support")
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>> ---
>>  sound/isa/cs423x/cs4236.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/sound/isa/cs423x/cs4236.c b/sound/isa/cs423x/cs4236.c
>> index 70559e59d18f..2211c39d2c18 100644
>> --- a/sound/isa/cs423x/cs4236.c
>> +++ b/sound/isa/cs423x/cs4236.c
>> @@ -292,7 +292,7 @@ static int snd_cs423x_pnp_init_mpu(int dev, struct pnp_dev *pdev)
>>  		mpu_irq[dev] = SNDRV_AUTO_IRQ;
>>  	} else {
>>  		mpu_port[dev] = pnp_port_start(pdev, 0);
>> -		if (mpu_irq[dev] >= 0 &&
>> +		if (!mpu_irq[dev] &&
>>  		    pnp_irq_valid(pdev, 0) && pnp_irq(pdev, 0) >= 0) {
>>  			mpu_irq[dev] = pnp_irq(pdev, 0);
>>  		} else {
>> -- 
>> 2.17.1
>>
>>

Patch
diff mbox series

diff --git a/sound/isa/cs423x/cs4236.c b/sound/isa/cs423x/cs4236.c
index 70559e59d18f..2211c39d2c18 100644
--- a/sound/isa/cs423x/cs4236.c
+++ b/sound/isa/cs423x/cs4236.c
@@ -292,7 +292,7 @@  static int snd_cs423x_pnp_init_mpu(int dev, struct pnp_dev *pdev)
 		mpu_irq[dev] = SNDRV_AUTO_IRQ;
 	} else {
 		mpu_port[dev] = pnp_port_start(pdev, 0);
-		if (mpu_irq[dev] >= 0 &&
+		if (!mpu_irq[dev] &&
 		    pnp_irq_valid(pdev, 0) && pnp_irq(pdev, 0) >= 0) {
 			mpu_irq[dev] = pnp_irq(pdev, 0);
 		} else {