On 06/29/2015 11:18 PM, 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.
>
> Fixes: 417d2e507edc ("[media] media: platform: add VPFE capture driver support for AM437X")
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.0+
> Signed-off-by: Benoit Parrot <bparrot@xxxxxx>
> ---
> Changes since v2:
> - fix the stable commit reference syntax
>
> 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 a30cc2f7e4f1..eb25c43da126 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);
Close, but no cigar.
The assignment to fh_singular should be moved inside the mutex. Right now
there still is a race condition between setting fh_singular and taking
the lock.
Regards,
Hans
> 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;
>
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