| Message ID | 20250307093140.370061-6-mathis.foerst@mt.com |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
Hi Mathis, Thank you for the patch. On Fri, Mar 07, 2025 at 10:31:39AM +0100, Mathis Foerst wrote: > Getting / Setting the frame interval using the V4L2 subdev pad ops > get_frame_interval/set_frame_interval causes a deadlock, as the > subdev state is locked in the [1] but also in the driver itself. > > In [2] it's described that the caller is responsible to acquire and > release the lock in this case. Therefore, acquiring the lock in the > driver is wrong. > > Remove the lock acquisitions/releases from mt9m114_ifp_get_frame_interval() > and mt9m114_ifp_set_frame_interval(). > > [1] drivers/media/v4l2-core/v4l2-subdev.c - line 1129 > [2] Documentation/driver-api/media/v4l2-subdev.rst > > Fixes: 24d756e914fc ("media: i2c: Add driver for onsemi MT9M114 camera sensor") > Cc: stable@vger.kernel.org > You can delete this blank line. > Signed-off-by: Mathis Foerst <mathis.foerst@mt.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > --- > drivers/media/i2c/mt9m114.c | 8 -------- > 1 file changed, 8 deletions(-) > > diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c > index 65b9124e464f..79c97ab19be9 100644 > --- a/drivers/media/i2c/mt9m114.c > +++ b/drivers/media/i2c/mt9m114.c > @@ -1644,13 +1644,9 @@ static int mt9m114_ifp_get_frame_interval(struct v4l2_subdev *sd, > if (interval->which != V4L2_SUBDEV_FORMAT_ACTIVE) > return -EINVAL; > > - mutex_lock(sensor->ifp.hdl.lock); > - > ival->numerator = 1; > ival->denominator = sensor->ifp.frame_rate; > > - mutex_unlock(sensor->ifp.hdl.lock); > - > return 0; > } > > @@ -1669,8 +1665,6 @@ static int mt9m114_ifp_set_frame_interval(struct v4l2_subdev *sd, > if (interval->which != V4L2_SUBDEV_FORMAT_ACTIVE) > return -EINVAL; > > - mutex_lock(sensor->ifp.hdl.lock); > - > if (ival->numerator != 0 && ival->denominator != 0) > sensor->ifp.frame_rate = min_t(unsigned int, > ival->denominator / ival->numerator, > @@ -1684,8 +1678,6 @@ static int mt9m114_ifp_set_frame_interval(struct v4l2_subdev *sd, > if (sensor->streaming) > ret = mt9m114_set_frame_rate(sensor); > > - mutex_unlock(sensor->ifp.hdl.lock); > - > return ret; > } >
diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c index 65b9124e464f..79c97ab19be9 100644 --- a/drivers/media/i2c/mt9m114.c +++ b/drivers/media/i2c/mt9m114.c @@ -1644,13 +1644,9 @@ static int mt9m114_ifp_get_frame_interval(struct v4l2_subdev *sd, if (interval->which != V4L2_SUBDEV_FORMAT_ACTIVE) return -EINVAL; - mutex_lock(sensor->ifp.hdl.lock); - ival->numerator = 1; ival->denominator = sensor->ifp.frame_rate; - mutex_unlock(sensor->ifp.hdl.lock); - return 0; } @@ -1669,8 +1665,6 @@ static int mt9m114_ifp_set_frame_interval(struct v4l2_subdev *sd, if (interval->which != V4L2_SUBDEV_FORMAT_ACTIVE) return -EINVAL; - mutex_lock(sensor->ifp.hdl.lock); - if (ival->numerator != 0 && ival->denominator != 0) sensor->ifp.frame_rate = min_t(unsigned int, ival->denominator / ival->numerator, @@ -1684,8 +1678,6 @@ static int mt9m114_ifp_set_frame_interval(struct v4l2_subdev *sd, if (sensor->streaming) ret = mt9m114_set_frame_rate(sensor); - mutex_unlock(sensor->ifp.hdl.lock); - return ret; }
Getting / Setting the frame interval using the V4L2 subdev pad ops get_frame_interval/set_frame_interval causes a deadlock, as the subdev state is locked in the [1] but also in the driver itself. In [2] it's described that the caller is responsible to acquire and release the lock in this case. Therefore, acquiring the lock in the driver is wrong. Remove the lock acquisitions/releases from mt9m114_ifp_get_frame_interval() and mt9m114_ifp_set_frame_interval(). [1] drivers/media/v4l2-core/v4l2-subdev.c - line 1129 [2] Documentation/driver-api/media/v4l2-subdev.rst Fixes: 24d756e914fc ("media: i2c: Add driver for onsemi MT9M114 camera sensor") Cc: stable@vger.kernel.org Signed-off-by: Mathis Foerst <mathis.foerst@mt.com> --- drivers/media/i2c/mt9m114.c | 8 -------- 1 file changed, 8 deletions(-)