On Thu, 2020-01-16 at 12:57 +0100, Hans Verkuil wrote:
> On 11/20/19 1:22 PM, Dafna Hirschfeld wrote:
> > sd->devnode is released after calling
> > v4l2_subdev_release. Therefore it should be set
> > to NULL so that the subdev won't hold a pointer
> > to a released object. This fixes a reference
> > after free bug in function
> > v4l2_device_unregister_subdev
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Fixes: 0e43734d4c46e ("media: v4l2-subdev: add release() internal op")
> > Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>
> > Reviewed-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>
> > ---
> > changes since v2:
> > - since this is a regresion fix, I added Fixes and Cc to stable tags,
> > - change the commit title and log to be more clear.
> >
> > drivers/media/v4l2-core/v4l2-device.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c
> > index 63d6b147b21e..2b3595671d62 100644
> > --- a/drivers/media/v4l2-core/v4l2-device.c
> > +++ b/drivers/media/v4l2-core/v4l2-device.c
> > @@ -177,6 +177,7 @@ static void v4l2_subdev_release(struct v4l2_subdev *sd)
> > {
> > struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;
> >
> > + sd->devnode = NULL;
> > if (sd->internal_ops && sd->internal_ops->release)
> > sd->internal_ops->release(sd);
>
> I'd move the sd->devnode = NULL; line here. That way the
> sd->internal_ops->release(sd) callback can still use it.
>
Hi everyone,
Please note this fix is useful to fix a kernel oops
when rkisp1 driver is removed.
Can we get a v4 addressing Hans' feedback?
Thanks,
Ezequiel
> Unless I am missing something?
>
> > module_put(owner);
> >
>
> Regards,
>
> Hans
