media: i2c: ov5648: Plug runtime pm counter leak
Commit Message
When the stream is being enabled, the runtime pm usage counter is
incremented. Then if ov5648_sw_standby() fails, the function returns
error without decrementing the counter, leaking it.
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
---
Hi,
I spotted this when converting OV5640 driver to use runtime PM using
this driver as reference. I only have a very surface level understanding
of runtime PM system as of now so please review with that in mind.
This patch is only compile-tested since I don't have the hardware with
me.
drivers/media/i2c/ov5648.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--
2.30.0
Comments
Hi Pratyush,
Thanks for the patch.
On Tue, May 11, 2021 at 06:14:37PM +0530, Pratyush Yadav wrote:
> When the stream is being enabled, the runtime pm usage counter is
> incremented. Then if ov5648_sw_standby() fails, the function returns
> error without decrementing the counter, leaking it.
>
> Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
> ---
>
> Hi,
>
> I spotted this when converting OV5640 driver to use runtime PM using
> this driver as reference. I only have a very surface level understanding
> of runtime PM system as of now so please review with that in mind.
>
> This patch is only compile-tested since I don't have the hardware with
> me.
>
> drivers/media/i2c/ov5648.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/i2c/ov5648.c b/drivers/media/i2c/ov5648.c
> index 3ecb4a3e8773..6aa2c950f505 100644
> --- a/drivers/media/i2c/ov5648.c
> +++ b/drivers/media/i2c/ov5648.c
> @@ -2143,8 +2143,12 @@ static int ov5648_s_stream(struct v4l2_subdev *subdev, int enable)
> ret = ov5648_sw_standby(sensor, !enable);
> mutex_unlock(&sensor->mutex);
>
> - if (ret)
> + if (ret) {
> + if (enable)
> + pm_runtime_put(sensor->dev);
The function powers the sensor off at the end if streaming was to be
disabled. You could do:
if (ret || !enable)
pm_runtime_put(sensor->dev);
> +
> return ret;
> + }
>
> state->streaming = !!enable;
state->streaming is assigned when not holding the lock. Could you address
that at the same time?
@@ -2143,8 +2143,12 @@ static int ov5648_s_stream(struct v4l2_subdev *subdev, int enable)
ret = ov5648_sw_standby(sensor, !enable);
mutex_unlock(&sensor->mutex);
- if (ret)
+ if (ret) {
+ if (enable)
+ pm_runtime_put(sensor->dev);
+
return ret;
+ }
state->streaming = !!enable;