[Patch 1/1] media: am437x-vpfe: Fix a race condition during release

[Patch 1/1] media: am437x-vpfe: Fix a race condition during release

[Benoit Parrot]

There was a race condition where during cleanup/release operation
on-going streaming would cause a kernel panic because the hardware
module was disabled prematurely with IRQ still pending.

Signed-off-by: Benoit Parrot <bparrot@ti.com>
---
 drivers/media/platform/am437x/am437x-vpfe.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/am437x/am437x-vpfe.c b/drivers/media/platform/am437x/am437x-vpfe.c
index a30cc2f..eb25c43 100644
--- a/drivers/media/platform/am437x/am437x-vpfe.c
+++ b/drivers/media/platform/am437x/am437x-vpfe.c
@@ -1185,14 +1185,21 @@ static int vpfe_initialize_device(struct vpfe_device *vpfe)
 static int vpfe_release(struct file *file)
 {
 	struct vpfe_device *vpfe = video_drvdata(file);
+	bool fh_singular = v4l2_fh_is_singular_file(file);
 	int ret;
 
 	mutex_lock(&vpfe->lock);
 
-	if (v4l2_fh_is_singular_file(file))
-		vpfe_ccdc_close(&vpfe->ccdc, vpfe->pdev);
+	/* the release helper will cleanup any on-going streaming */
 	ret = _vb2_fop_release(file, NULL);
 
+	/*
+	 * If this was the last open file.
+	 * Then de-initialize hw module.
+	 */
+	if (fh_singular)
+		vpfe_ccdc_close(&vpfe->ccdc, vpfe->pdev);
+
 	mutex_unlock(&vpfe->lock);
 
 	return ret;
-- 
1.8.5.1

Re: [Patch 1/1] media: am437x-vpfe: Fix a race condition during release

[Felipe Balbi]

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On Mon, Jun 29, 2015 at 02:41:53PM -0500, Benoit Parrot wrote:
> There was a race condition where during cleanup/release operation
> on-going streaming would cause a kernel panic because the hardware
> module was disabled prematurely with IRQ still pending.
> 
> Signed-off-by: Benoit Parrot <bparrot@ti.com>

should this go to stable too ?

> ---
>  drivers/media/platform/am437x/am437x-vpfe.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/platform/am437x/am437x-vpfe.c b/drivers/media/platform/am437x/am437x-vpfe.c
> index a30cc2f..eb25c43 100644
> --- a/drivers/media/platform/am437x/am437x-vpfe.c
> +++ b/drivers/media/platform/am437x/am437x-vpfe.c
> @@ -1185,14 +1185,21 @@ static int vpfe_initialize_device(struct vpfe_device *vpfe)
>  static int vpfe_release(struct file *file)
>  {
>  	struct vpfe_device *vpfe = video_drvdata(file);
> +	bool fh_singular = v4l2_fh_is_singular_file(file);
>  	int ret;
>  
>  	mutex_lock(&vpfe->lock);
>  
> -	if (v4l2_fh_is_singular_file(file))
> -		vpfe_ccdc_close(&vpfe->ccdc, vpfe->pdev);
> +	/* the release helper will cleanup any on-going streaming */
>  	ret = _vb2_fop_release(file, NULL);
>  
> +	/*
> +	 * If this was the last open file.
> +	 * Then de-initialize hw module.
> +	 */
> +	if (fh_singular)
> +		vpfe_ccdc_close(&vpfe->ccdc, vpfe->pdev);
> +
>  	mutex_unlock(&vpfe->lock);
>  
>  	return ret;
> -- 
> 1.8.5.1
> 
> --
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-- 
balbi

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