[PATCH] dmaengine: sprd: Cleanup in .remove() after pm_runtime_get_sync() failed

[PATCH] dmaengine: sprd: Cleanup in .remove() after pm_runtime_get_sync() failed

[Uwe Kleine-König]

It's not allowed to quit remove early without cleaning up completely.
Otherwise this results in resource leaks that probably yield graver
problems later. Here for example some tasklets might survive the lifetime
of the sprd-dma device and access sdev which is freed after .remove()
returns.

As none of the device freeing requires an active device, just ignore the
return value of pm_runtime_get_sync().

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/dma/sprd-dma.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
index 2138b80435ab..474d3ba8ec9f 100644
--- a/drivers/dma/sprd-dma.c
+++ b/drivers/dma/sprd-dma.c
@@ -1237,11 +1237,8 @@ static int sprd_dma_remove(struct platform_device *pdev)
 {
 	struct sprd_dma_dev *sdev = platform_get_drvdata(pdev);
 	struct sprd_dma_chn *c, *cn;
-	int ret;
 
-	ret = pm_runtime_get_sync(&pdev->dev);
-	if (ret < 0)
-		return ret;
+	pm_runtime_get_sync(&pdev->dev);
 
 	/* explicitly free the irq */
 	if (sdev->irq > 0)

base-commit: f2906aa863381afb0015a9eb7fefad885d4e5a56
-- 
2.36.1

Re: [PATCH] dmaengine: sprd: Cleanup in .remove() after pm_runtime_get_sync() failed

[Baolin Wang]

On Fri, Jul 22, 2022 at 4:41 AM Uwe Kleine-König
<u.kleine-koenig@pengutronix.de> wrote:
>
> It's not allowed to quit remove early without cleaning up completely.
> Otherwise this results in resource leaks that probably yield graver
> problems later. Here for example some tasklets might survive the lifetime
> of the sprd-dma device and access sdev which is freed after .remove()
> returns.
>
> As none of the device freeing requires an active device, just ignore the
> return value of pm_runtime_get_sync().
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

It makes sense to me. Thanks.
Reviewed-by: Baolin Wang <baolin.wang7@gmail.com>

> ---
>  drivers/dma/sprd-dma.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
> index 2138b80435ab..474d3ba8ec9f 100644
> --- a/drivers/dma/sprd-dma.c
> +++ b/drivers/dma/sprd-dma.c
> @@ -1237,11 +1237,8 @@ static int sprd_dma_remove(struct platform_device *pdev)
>  {
>         struct sprd_dma_dev *sdev = platform_get_drvdata(pdev);
>         struct sprd_dma_chn *c, *cn;
> -       int ret;
>
> -       ret = pm_runtime_get_sync(&pdev->dev);
> -       if (ret < 0)
> -               return ret;
> +       pm_runtime_get_sync(&pdev->dev);
>
>         /* explicitly free the irq */
>         if (sdev->irq > 0)
>
> base-commit: f2906aa863381afb0015a9eb7fefad885d4e5a56
> --
> 2.36.1
>


-- 
Baolin Wang

Re: [PATCH] dmaengine: sprd: Cleanup in .remove() after pm_runtime_get_sync() failed

[Uwe Kleine-König]

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On Thu, Jul 21, 2022 at 10:40:54PM +0200, Uwe Kleine-König wrote:
> It's not allowed to quit remove early without cleaning up completely.
> Otherwise this results in resource leaks that probably yield graver
> problems later. Here for example some tasklets might survive the lifetime
> of the sprd-dma device and access sdev which is freed after .remove()
> returns.
> 
> As none of the device freeing requires an active device, just ignore the
> return value of pm_runtime_get_sync().
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

If you want a fixes line, that would be:

Fixes: 9b3b8171f7f4 ("dmaengine: sprd: Add Spreadtrum DMA driver")

but I'm not sure this is critical enough to be backported to stable. So
apply at will.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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Re: [PATCH] dmaengine: sprd: Cleanup in .remove() after pm_runtime_get_sync() failed

[Vinod Koul]

On 21-07-22, 22:40, Uwe Kleine-König wrote:
> It's not allowed to quit remove early without cleaning up completely.
> Otherwise this results in resource leaks that probably yield graver
> problems later. Here for example some tasklets might survive the lifetime
> of the sprd-dma device and access sdev which is freed after .remove()
> returns.
> 
> As none of the device freeing requires an active device, just ignore the
> return value of pm_runtime_get_sync().

Applied, thanks

> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
>  drivers/dma/sprd-dma.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
> index 2138b80435ab..474d3ba8ec9f 100644
> --- a/drivers/dma/sprd-dma.c
> +++ b/drivers/dma/sprd-dma.c
> @@ -1237,11 +1237,8 @@ static int sprd_dma_remove(struct platform_device *pdev)
>  {
>  	struct sprd_dma_dev *sdev = platform_get_drvdata(pdev);
>  	struct sprd_dma_chn *c, *cn;
> -	int ret;
>  
> -	ret = pm_runtime_get_sync(&pdev->dev);
> -	if (ret < 0)
> -		return ret;
> +	pm_runtime_get_sync(&pdev->dev);
>  
>  	/* explicitly free the irq */
>  	if (sdev->irq > 0)
> 
> base-commit: f2906aa863381afb0015a9eb7fefad885d4e5a56
> -- 
> 2.36.1

-- 
~Vinod