Re: [patch] IR: ene_ir: problems in unwinding on probe

[Maxim Levitsky <maximlevitsky@gmail.com>]

On Thu, 2010-08-12 at 09:46 +0200, Dan Carpenter wrote: 
> There were a couple issues here.  If the allocation failed for "dev"
> then it would lead to a NULL dereference.  If request_irq() or
> request_region() failed it would release the irq and the region even
> though they were not successfully aquired.
> 
> Signed-off-by: Dan Carpenter <error27@gmail.com>

I don't think this is needed.
I just alloc all the stuff, and if one of allocations fail, I free them
all. {k}free on NULL pointer is perfectly legal.

Same about IO and IRQ.
IRQ0 and IO 0 isn't valid, and I do test that in error path.


Best regards,
Maxim Levitsky


> 
> diff --git a/drivers/media/IR/ene_ir.c b/drivers/media/IR/ene_ir.c
> index 5447750..8e5e964 100644
> --- a/drivers/media/IR/ene_ir.c
> +++ b/drivers/media/IR/ene_ir.c
> @@ -781,21 +781,24 @@ static int ene_probe(struct pnp_dev *pnp_dev, const struct pnp_device_id *id)
>  
>  	/* allocate memory */
>  	input_dev = input_allocate_device();
> +	if (!input_dev)
> +		goto err_out;
>  	ir_props = kzalloc(sizeof(struct ir_dev_props), GFP_KERNEL);
> +	if (!ir_props)
> +		goto err_input_dev;
>  	dev = kzalloc(sizeof(struct ene_device), GFP_KERNEL);
> -
> -	if (!input_dev || !ir_props || !dev)
> -		goto error;
> +	if (!dev)
> +		goto err_ir_props;
>  
>  	/* validate resources */
>  	error = -ENODEV;
>  
>  	if (!pnp_port_valid(pnp_dev, 0) ||
>  	    pnp_port_len(pnp_dev, 0) < ENE_MAX_IO)
> -		goto error;
> +		goto err_dev;
>  
>  	if (!pnp_irq_valid(pnp_dev, 0))
> -		goto error;
> +		goto err_dev;
>  
>  	dev->hw_io = pnp_port_start(pnp_dev, 0);
>  	dev->irq = pnp_irq(pnp_dev, 0);
> @@ -804,11 +807,11 @@ static int ene_probe(struct pnp_dev *pnp_dev, const struct pnp_device_id *id)
>  	/* claim the resources */
>  	error = -EBUSY;
>  	if (!request_region(dev->hw_io, ENE_MAX_IO, ENE_DRIVER_NAME))
> -		goto error;
> +		goto err_dev;
>  
>  	if (request_irq(dev->irq, ene_isr,
>  			IRQF_SHARED, ENE_DRIVER_NAME, (void *)dev))
> -		goto error;
> +		goto err_region;
>  
>  	pnp_set_drvdata(pnp_dev, dev);
>  	dev->pnp_dev = pnp_dev;
> @@ -816,7 +819,7 @@ static int ene_probe(struct pnp_dev *pnp_dev, const struct pnp_device_id *id)
>  	/* detect hardware version and features */
>  	error = ene_hw_detect(dev);
>  	if (error)
> -		goto error;
> +		goto err_irq;
>  
>  	ene_setup_settings(dev);
>  
> @@ -889,20 +892,22 @@ static int ene_probe(struct pnp_dev *pnp_dev, const struct pnp_device_id *id)
>  	error = -ENODEV;
>  	if (ir_input_register(input_dev, RC_MAP_RC6_MCE, ir_props,
>  							ENE_DRIVER_NAME))
> -		goto error;
> -
> +		goto err_irq;
>  
>  	ene_printk(KERN_NOTICE, "driver has been succesfully loaded\n");
>  	return 0;
> -error:
> -	if (dev->irq)
> -		free_irq(dev->irq, dev);
> -	if (dev->hw_io)
> -		release_region(dev->hw_io, ENE_MAX_IO);
>  
> -	input_free_device(input_dev);
> -	kfree(ir_props);
> +err_irq:
> +	free_irq(dev->irq, dev);
> +err_region:
> +	release_region(dev->hw_io, ENE_MAX_IO);
> +err_dev:
>  	kfree(dev);
> +err_ir_props:
> +	kfree(ir_props);
> +err_input_dev:
> +	input_free_device(input_dev);
> +err_out:
>  	return error;
>  }
>