[PATCH] [media] dib0700: unlock mutexes on error paths

[PATCH] [media] dib0700: unlock mutexes on error paths

[Alexey Khoroshilov]

dib0700_i2c_xfer [_new and _legacy] leave i2c_mutex locked on error paths.
The patch adds appropriate unlocks.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
---
 drivers/media/dvb/dvb-usb/dib0700_core.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/media/dvb/dvb-usb/dib0700_core.c b/drivers/media/dvb/dvb-usb/dib0700_core.c
index 070e82a..8ec22c4 100644
--- a/drivers/media/dvb/dvb-usb/dib0700_core.c
+++ b/drivers/media/dvb/dvb-usb/dib0700_core.c
@@ -228,7 +228,7 @@ static int dib0700_i2c_xfer_new(struct i2c_adapter *adap, struct i2c_msg *msg,
 			/* Write request */
 			if (mutex_lock_interruptible(&d->usb_mutex) < 0) {
 				err("could not acquire lock");
-				return 0;
+				break;
 			}
 			st->buf[0] = REQUEST_NEW_I2C_WRITE;
 			st->buf[1] = msg[i].addr << 1;
@@ -270,11 +270,14 @@ static int dib0700_i2c_xfer_legacy(struct i2c_adapter *adap,
 	struct dib0700_state *st = d->priv;
 	int i,len;
 
-	if (mutex_lock_interruptible(&d->i2c_mutex) < 0)
+	if (mutex_lock_interruptible(&d->i2c_mutex) < 0) {
+		err("could not acquire lock");
 		return -EAGAIN;
+	}
 	if (mutex_lock_interruptible(&d->usb_mutex) < 0) {
+		mutex_unlock(&d->i2c_mutex);
 		err("could not acquire lock");
-		return 0;
+		return -EAGAIN;
 	}
 
 	for (i = 0; i < num; i++) {
-- 
1.7.4.1

Re: [PATCH] [media] dib0700: unlock mutexes on error paths

[Mauro Carvalho Chehab]

Em 07-03-2012 16:21, Alexey Khoroshilov escreveu:
> dib0700_i2c_xfer [_new and _legacy] leave i2c_mutex locked on error paths.
> The patch adds appropriate unlocks.
> 
> Found by Linux Driver Verification project (linuxtesting.org).
> 
> Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
> ---
>  drivers/media/dvb/dvb-usb/dib0700_core.c |    9 ++++++---
>  1 files changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/media/dvb/dvb-usb/dib0700_core.c b/drivers/media/dvb/dvb-usb/dib0700_core.c
> index 070e82a..8ec22c4 100644
> --- a/drivers/media/dvb/dvb-usb/dib0700_core.c
> +++ b/drivers/media/dvb/dvb-usb/dib0700_core.c
> @@ -228,7 +228,7 @@ static int dib0700_i2c_xfer_new(struct i2c_adapter *adap, struct i2c_msg *msg,
>  			/* Write request */
>  			if (mutex_lock_interruptible(&d->usb_mutex) < 0) {
>  				err("could not acquire lock");
> -				return 0;
> +				break;

A break here doesn't sound the right thing to do.

>  			}
>  			st->buf[0] = REQUEST_NEW_I2C_WRITE;
>  			st->buf[1] = msg[i].addr << 1;
> @@ -270,11 +270,14 @@ static int dib0700_i2c_xfer_legacy(struct i2c_adapter *adap,
>  	struct dib0700_state *st = d->priv;
>  	int i,len;
>  
> -	if (mutex_lock_interruptible(&d->i2c_mutex) < 0)
> +	if (mutex_lock_interruptible(&d->i2c_mutex) < 0) {
> +		err("could not acquire lock");
>  		return -EAGAIN;
> +	}
>  	if (mutex_lock_interruptible(&d->usb_mutex) < 0) {
> +		mutex_unlock(&d->i2c_mutex);
>  		err("could not acquire lock");
> -		return 0;
> +		return -EAGAIN;
>  	}
>  
>  	for (i = 0; i < num; i++) {

Re: [PATCH] [media] dib0700: unlock mutexes on error paths

[Alexey Khoroshilov]

 On Mon, 19 Mar 2012 14:47:54 -0300, Mauro Carvalho Chehab 
 <mchehab@redhat.com> wrote:
> Em 07-03-2012 16:21, Alexey Khoroshilov escreveu:
>> dib0700_i2c_xfer [_new and _legacy] leave i2c_mutex locked on error 
>> paths.
>> The patch adds appropriate unlocks.
>>
>> Found by Linux Driver Verification project (linuxtesting.org).
>>
>> Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
>> ---
>>  drivers/media/dvb/dvb-usb/dib0700_core.c |    9 ++++++---
>>  1 files changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/media/dvb/dvb-usb/dib0700_core.c 
>> b/drivers/media/dvb/dvb-usb/dib0700_core.c
>> index 070e82a..8ec22c4 100644
>> --- a/drivers/media/dvb/dvb-usb/dib0700_core.c
>> +++ b/drivers/media/dvb/dvb-usb/dib0700_core.c
>> @@ -228,7 +228,7 @@ static int dib0700_i2c_xfer_new(struct 
>> i2c_adapter *adap, struct i2c_msg *msg,
>>  			/* Write request */
>>  			if (mutex_lock_interruptible(&d->usb_mutex) < 0) {
>>  				err("could not acquire lock");
>> -				return 0;
>> +				break;
>
> A break here doesn't sound the right thing to do.
>

 I am sorry, but I did not catch the issue.
 The break is almost equivalent to another one a few lines below that 
 happens when usb_control_msg() fails.

 Could you please clarify the problem?

 --
 Alexey