[PATCH] media: imx-jpeg: avoid double free on video register failure

[Guangshuo Li]

Hi Mirela,

On Mon, 25 May 2026 at 21:57, Mirela Rabulea <mirela.rabulea at nxp.com> wrote:
>
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> >
> > mxc_jpeg_probe() allocates a video_device with video_device_alloc() and
> > releases it from the err_vdev_register error path if
> > video_register_device() fails.
> >
> > This can double free the video_device when __video_register_device()
> > reaches device_register() and that call fails:
> >
> >    video_register_device()
> >      -> __video_register_device()
> >         -> device_register() fails
> >            -> put_device(&vdev->dev)
> >               -> v4l2_device_release()
> >                  -> vdev->release(vdev)
> >                     -> video_device_release(vdev)
> >
> >    mxc_jpeg_probe()
> >      -> err_vdev_register
> >         -> video_device_release(jpeg->dec_vdev)
> >
> > Use video_device_release_empty() while registering the device so that
> > registration failure paths do not free jpeg->dec_vdev through
> > vdev->release(). mxc_jpeg_probe() then releases jpeg->dec_vdev exactly
> > once from err_vdev_register. Restore video_device_release() after
> > successful registration so the registered device keeps its normal lifetime
> > handling.
> >
> > This issue was found by a static analysis tool I am developing.
> >
> > Fixes: 2db16c6ed72c ("media: imx-jpeg: Add V4L2 driver for i.MX8 JPEG Encoder/Decoder")
> > Signed-off-by: Guangshuo Li <lgs201920130244 at gmail.com>
>
> Hi Guangshuo,
>
> sorry for the late response, so I assume this patch will be dropped in
> favor of a fix in v4l2-core, as per discussions here?:
>
> https://lore.kernel.org/linux-media/20260519090819.1041314-1-lgs201920130244@gmail.com/
>
> Thanks,
>
> Mirela
>
> > ---
> >   drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
> > index b442dcba02e7..fe8a373576ef 100644
> > --- a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
> > +++ b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
> > @@ -2943,7 +2943,7 @@ static int mxc_jpeg_probe(struct platform_device *pdev)
> >          jpeg->dec_vdev->fops = &mxc_jpeg_fops;
> >          jpeg->dec_vdev->ioctl_ops = &mxc_jpeg_ioctl_ops;
> >          jpeg->dec_vdev->minor = -1;
> > -       jpeg->dec_vdev->release = video_device_release;
> > +       jpeg->dec_vdev->release = video_device_release_empty;
> >          jpeg->dec_vdev->lock = &jpeg->lock; /* lock for ioctl serialization */
> >          jpeg->dec_vdev->v4l2_dev = &jpeg->v4l2_dev;
> >          jpeg->dec_vdev->vfl_dir = VFL_DIR_M2M;
> > @@ -2962,6 +2962,8 @@ static int mxc_jpeg_probe(struct platform_device *pdev)
> >                  dev_err(dev, "failed to register video device\n");
> >                  goto err_vdev_register;
> >          }
> > +       jpeg->dec_vdev->release = video_device_release;
> > +
> >          if (mode == MXC_JPEG_ENCODE)
> >                  v4l2_info(&jpeg->v4l2_dev,
> >                            "encoder device registered as /dev/video%d (%d,%d)\n",
> > --
> > 2.43.0
> >
Yes, you are right. Please drop this patch.

As discussed in the related thread, this issue should be fixed in
v4l2-core instead of handling it in the imx-jpeg driver.

Thanks for checking.

Best regards,
Guangshuo