[PATCH] firmware: stratix10-svc: Fix a resource leak in an error handling path

[PATCH] firmware: stratix10-svc: Fix a resource leak in an error handling path

[Christophe JAILLET]

If an error occurs after a successful 'kfifo_alloc()' call, it must be
undone by a corresponding 'kfifo_free()' call, as already done in the
remove function.

While at it, move the 'platform_device_put()' call to this new error
handling path and explicitly return 0 in the success path.

Fixes: b5dc75c915cd ("firmware: stratix10-svc: extend svc to support new RSU features")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
 drivers/firmware/stratix10-svc.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/firmware/stratix10-svc.c b/drivers/firmware/stratix10-svc.c
index 3aa489dba30a..2a7687911c09 100644
--- a/drivers/firmware/stratix10-svc.c
+++ b/drivers/firmware/stratix10-svc.c
@@ -1034,24 +1034,32 @@ static int stratix10_svc_drv_probe(struct platform_device *pdev)
 
 	/* add svc client device(s) */
 	svc = devm_kzalloc(dev, sizeof(*svc), GFP_KERNEL);
-	if (!svc)
-		return -ENOMEM;
+	if (!svc) {
+		ret = -ENOMEM;
+		goto err_free_kfifo;
+	}
 
 	svc->stratix10_svc_rsu = platform_device_alloc(STRATIX10_RSU, 0);
 	if (!svc->stratix10_svc_rsu) {
 		dev_err(dev, "failed to allocate %s device\n", STRATIX10_RSU);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto err_free_kfifo;
 	}
 
 	ret = platform_device_add(svc->stratix10_svc_rsu);
-	if (ret) {
-		platform_device_put(svc->stratix10_svc_rsu);
-		return ret;
-	}
+	if (ret)
+		goto err_put_device;
+
 	dev_set_drvdata(dev, svc);
 
 	pr_info("Intel Service Layer Driver Initialized\n");
 
+	return 0;
+
+err_put_device:
+	platform_device_put(svc->stratix10_svc_rsu);
+err_free_kfifo:
+	kfifo_free(&controller->svc_fifo);
 	return ret;
 }
 
-- 
2.30.2

Re: [PATCH] firmware: stratix10-svc: Fix a resource leak in an error handling path

[Richard Gong]

Hi Jaillet,

Thanks!

On 5/21/21 1:22 PM, Christophe JAILLET wrote:
> If an error occurs after a successful 'kfifo_alloc()' call, it must be
> undone by a corresponding 'kfifo_free()' call, as already done in the
> remove function.
> 
> While at it, move the 'platform_device_put()' call to this new error
> handling path and explicitly return 0 in the success path.
> 
> Fixes: b5dc75c915cd ("firmware: stratix10-svc: extend svc to support new RSU features")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
>   drivers/firmware/stratix10-svc.c | 22 +++++++++++++++-------
>   1 file changed, 15 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/firmware/stratix10-svc.c b/drivers/firmware/stratix10-svc.c
> index 3aa489dba30a..2a7687911c09 100644
> --- a/drivers/firmware/stratix10-svc.c
> +++ b/drivers/firmware/stratix10-svc.c
> @@ -1034,24 +1034,32 @@ static int stratix10_svc_drv_probe(struct platform_device *pdev)
>   
>   	/* add svc client device(s) */
>   	svc = devm_kzalloc(dev, sizeof(*svc), GFP_KERNEL);
> -	if (!svc)
> -		return -ENOMEM;
> +	if (!svc) {
> +		ret = -ENOMEM;
> +		goto err_free_kfifo;
> +	}
>   
>   	svc->stratix10_svc_rsu = platform_device_alloc(STRATIX10_RSU, 0);
>   	if (!svc->stratix10_svc_rsu) {
>   		dev_err(dev, "failed to allocate %s device\n", STRATIX10_RSU);
> -		return -ENOMEM;
> +		ret = -ENOMEM;
> +		goto err_free_kfifo;
>   	}
>   
>   	ret = platform_device_add(svc->stratix10_svc_rsu);
> -	if (ret) {
> -		platform_device_put(svc->stratix10_svc_rsu);
> -		return ret;
> -	}
> +	if (ret)
> +		goto err_put_device;
> +
>   	dev_set_drvdata(dev, svc);
>   
>   	pr_info("Intel Service Layer Driver Initialized\n");
>   
> +	return 0;
> +
> +err_put_device:
> +	platform_device_put(svc->stratix10_svc_rsu);
> +err_free_kfifo:
> +	kfifo_free(&controller->svc_fifo);

Need for the allocated memory pool as well,
	if (ctrl->genpool)
                 gen_pool_destroy(ctrl->genpool);

Rename err_free_kfifo to include both.

>   	return ret;
>   }
>   
> 

Regards,
Richard

Re: [PATCH] firmware: stratix10-svc: Fix a resource leak in an error handling path

[Dan Carpenter]

On Wed, May 26, 2021 at 02:13:12PM -0500, Richard Gong wrote:
> >   	dev_set_drvdata(dev, svc);
> >   	pr_info("Intel Service Layer Driver Initialized\n");
> > +	return 0;
> > +
> > +err_put_device:
> > +	platform_device_put(svc->stratix10_svc_rsu);
> > +err_free_kfifo:
> > +	kfifo_free(&controller->svc_fifo);
> 
> Need for the allocated memory pool as well,
> 	if (ctrl->genpool)
>                 gen_pool_destroy(ctrl->genpool);
> 

Good point, but there is no need to check, the genpool is not optional
and the "if (ctrl->genpool)" condition could be deleted from the remove
function as well.

err_put_device:
	platform_device_put(svc->stratix10_svc_rsu);
err_free_kfifo:
	kfifo_free(&controller->svc_fifo);
err_destroy_pool:
	gen_pool_destroy(genpool);

	return ret;

But the other question is what's on with the &svc_ctrl list?  I would
have thought that we needed to remove freed controller from the list as
well, but looking at it now I think the list itself should be removed.
I think there can only be one item in the list at a time.  So we could
just make the controller pointer a file scope global or we could find
some other way to go from the client pointer to the controller pointer.

regards,
dan carpenter