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

[Liang He]

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


Thanks a lot,


Liang

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