Re: [PATCH 4.19 047/125] media: davinci: vpif_capture: fix potential double free

Pavel Machek
2020-09-01T18:43:06Z

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Hi!

> [ Upstream commit 602649eadaa0c977e362e641f51ec306bc1d365d ]
>
> In case of errors vpif_probe_complete() releases memory for vpif_obj.sd
> and unregisters the V4L2 device. But then this is done again by
> vpif_probe() itself. The patch removes the cleaning from
> vpif_probe_complete().

> Signed-off-by: Evgeny Novikov <novikov@ispras.ru>
> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> drivers/media/platform/davinci/vpif_capture.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/drivers/media/platform/davinci/vpif_capture.c b/drivers/media/platform/davinci/vpif_capture.c
> index a96f53ce80886..cf1d11e6dd8c4 100644
> --- a/drivers/media/platform/davinci/vpif_capture.c
> +++ b/drivers/media/platform/davinci/vpif_capture.c
> @@ -1489,8 +1489,6 @@ probe_out:
> /* Unregister video device */
> video_unregister_device(&ch->video_dev);
> }
> - kfree(vpif_obj.sd);
> - v4l2_device_unregister(&vpif_obj.v4l2_dev);
>
> return err;
> }

This one is wrong. Unlike mainline, 4.19 does check return value of
vpif_probe_complete(), and thus it will lead to memory leak in 4.19.

Furthermore, I believe mainline still has a problems after this
patch. There is sync and async path where vpif_probe_complete(), and
while this fixes the sync path in mainline, I believe it will cause
memory leak on the async path.

Best regards,
Pavel

--
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