[PATCH] drm:bridge:analogix: Fix refcount bugs in anx7625_parse_dt()

[Robert Foss]

On Mon, 18 Jul 2022 at 15:35, Liang He <windhl at 126.com> wrote:
>
>
> At 2022-07-18 19:56:09, "Liang He" <windhl at 126.com> wrote:
> >
> >At 2022-07-18 19:54:18, "Robert Foss" <robert.foss at linaro.org> wrote:
> >>Hey Liang,
> >>
> >>
> >>On Thu, 7 Jul 2022 at 03:25, Liang He <windhl at 126.com> wrote:
> >>>
> >>> There are two refcount bugs in this funcion:
> >>>
> >>> BUG-1: 'pdata->mipi_host_node' will be assigned a new reference with
> >>> of_graph_get_remote_node() which will increase the refcount of the
> >>> object, correspondingly, we should call of_node_put() for the old
> >>> reference stored in the 'pdata->mipi_host_node'.
> >>>
> >>> BUG-2: of_graph_get_endpoint_by_regs() will also increase the refcount
> >>> of the object and its new reference will be assigned to local 'ep0', so
> >>> there should be a of_node_put() when 'ep0' is not used anymore.
> >>>
> >>> Fixes: 8bdfc5dae4e3 ("drm/bridge: anx7625: Add anx7625 MIPI DSI/DPI to DP")
> >>> Fixes: fd0310b6fe7d ("drm/bridge: anx7625: add MIPI DPI input feature")
> >>> Signed-off-by: Liang He <windhl at 126.com>
> >>> ---
> >>>  drivers/gpu/drm/bridge/analogix/anx7625.c | 2 ++
> >>>  1 file changed, 2 insertions(+)
> >>>
> >>> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> >>> index 53a5da6c49dd..f39b9be19eaf 100644
> >>> --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> >>> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> >>> @@ -1624,6 +1624,7 @@ static int anx7625_parse_dt(struct device *dev,
> >>>         anx7625_get_swing_setting(dev, pdata);
> >>>
> >>>         pdata->is_dpi = 1; /* default dpi mode */
> >>> +       of_node_put(pdata->mipi_host_node);
> >>>         pdata->mipi_host_node = of_graph_get_remote_node(np, 0, 0);
> >>>         if (!pdata->mipi_host_node) {
> >>>                 DRM_DEV_ERROR(dev, "fail to get internal panel.\n");
> >>> @@ -1638,6 +1639,7 @@ static int anx7625_parse_dt(struct device *dev,
> >>>                         bus_type = 0;
> >>>
> >>>                 mipi_lanes = of_property_count_u32_elems(ep0, "data-lanes");
> >>> +               of_node_put(ep0);
> >>>         }
> >>>
> >>>         if (bus_type == V4L2_FWNODE_BUS_TYPE_PARALLEL) /* bus type is Parallel(DSI) */
> >>> --
> >>> 2.25.1
> >>>
> >>
> >>This patch does not apply on drm-misc-next, could you please rebase it
> >>and send a v2?
>
> >>
>
>
> Hi, Rob, may I rebase it with linux-next/master ?

Ideally not, sometimes this will cause issues where I can't pull your patches.

> As I cannot find drm-misc-next, or can you teach me how to rebase that branch?

git remote add linux-misc git://anongit.freedesktop.org/drm/drm-misc
git fetch linux-misc
git rebase linux-misc/drm-misc-next

>
>
> Thanks a lot,
>
>
> Liang
>
> >>Rob.
> >
> >Thanks for your reply.
> >
> >I will rebase it soon.
> >
> >Liang