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

[Liang He]

At 2022-07-18 19:55:16, "Robert Foss" <robert.foss at linaro.org> wrote:
>On Mon, 18 Jul 2022 at 13:54, 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?
>
>Can you also fix the title, it should start with "drm/bridge: anx7625:"

Thanks, I will fix it in new patch.