On Fri, Apr 03, 2015 at 10:45:29AM +0300, Tommi Rantala wrote:
> Regression in commit 2caa80e72b57c6216aec6f6a11fcfb4fec46daa0
> Author: Daniel Vetter <daniel.vetter at ffwll.ch>
> Date: Sun Feb 22 11:38:36 2015 +0100
>
> drm: Fix deadlock due to getconnector locking changes
>
> If the drm_connector_find() call returns NULL, we should no longer
> call drm_modeset_unlock() to avoid locking imbalance.
>
> Signed-off-by: Tommi Rantala <tt.rantala at gmail.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Oops, thanks for catching this. If this missed 4.0 then we need to
backport it.
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
> drivers/gpu/drm/drm_crtc.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 679b10e..b6f076b 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -2121,7 +2121,7 @@ int drm_mode_getconnector(struct drm_device *dev, void
> *data,
> connector = drm_connector_find(dev, out_resp->connector_id);
> if (!connector) {
> ret = -ENOENT;
> - goto out;
> + goto out_unlock;
> }
>
> for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++)
> @@ -2201,6 +2201,8 @@ int drm_mode_getconnector(struct drm_device *dev, void
> *data,
>
> out:
> drm_modeset_unlock(&dev->mode_config.connection_mutex);
> +
> +out_unlock:
> mutex_unlock(&dev->mode_config.mutex);
>
> return ret;
> --
> 2.1.0
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
