On Tue, Jun 20, 2017 at 10:28:37PM +0200, Daniel Vetter wrote:
> In
>
> commit 91eefc05f0ac71902906b2058360e61bd25137fe
> Author: Daniel Vetter <daniel.vetter@xxxxxxxx>
> Date: Wed Dec 14 00:08:10 2016 +0100
>
> drm: Tighten locking in drm_mode_getconnector
>
> I reordered the logic a bit in that IOCTL, but that broke userspace
> since it'll get the new mode list, but not the new property values.
> Fix that again.
>
> v2: Fix up the error path handling when copy_to_user for the modes
> failes (Dhinakaran).
>
> Fixes: 91eefc05f0ac ("drm: Tighten locking in drm_mode_getconnector")
> Cc: Sean Paul <seanpaul@xxxxxxxxxxxx>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx>
> Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> Cc: David Airlie <airlied@xxxxxxxx>
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Reported-by: "H.J. Lu" <hjl.tools@xxxxxxxxx>
> Tested-by: "H.J. Lu" <hjl.tools@xxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.11+
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100576
> Cc: "H.J. Lu" <hjl.tools@xxxxxxxxx>
> Cc: "Pandiyan, Dhinakaran" <dhinakaran.pandiyan@xxxxxxxxx>
> Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Yep, lgtm
Reviewed-by: Sean Paul <seanpaul@xxxxxxxxxxxx>
> ---
> drivers/gpu/drm/drm_connector.c | 38 ++++++++++++++++++++------------------
> 1 file changed, 20 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index 5cd61aff7857..8072e6e4c62c 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -1293,21 +1293,6 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
> if (!connector)
> return -ENOENT;
>
> - drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
> - encoder = drm_connector_get_encoder(connector);
> - if (encoder)
> - out_resp->encoder_id = encoder->base.id;
> - else
> - out_resp->encoder_id = 0;
> -
> - ret = drm_mode_object_get_properties(&connector->base, file_priv->atomic,
> - (uint32_t __user *)(unsigned long)(out_resp->props_ptr),
> - (uint64_t __user *)(unsigned long)(out_resp->prop_values_ptr),
> - &out_resp->count_props);
> - drm_modeset_unlock(&dev->mode_config.connection_mutex);
> - if (ret)
> - goto out_unref;
> -
> for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++)
> if (connector->encoder_ids[i] != 0)
> encoders_count++;
> @@ -1320,7 +1305,7 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
> if (put_user(connector->encoder_ids[i],
> encoder_ptr + copied)) {
> ret = -EFAULT;
> - goto out_unref;
> + goto out;
> }
> copied++;
> }
> @@ -1364,15 +1349,32 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
> if (copy_to_user(mode_ptr + copied,
> &u_mode, sizeof(u_mode))) {
> ret = -EFAULT;
> + mutex_unlock(&dev->mode_config.mutex);
> +
> goto out;
> }
> copied++;
> }
> }
> out_resp->count_modes = mode_count;
> -out:
> mutex_unlock(&dev->mode_config.mutex);
> -out_unref:
> +
> + drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
> + encoder = drm_connector_get_encoder(connector);
> + if (encoder)
> + out_resp->encoder_id = encoder->base.id;
> + else
> + out_resp->encoder_id = 0;
> +
> + /* Only grab properties after probing, to make sure EDID and other
> + * properties reflect the latest status. */
> + ret = drm_mode_object_get_properties(&connector->base, file_priv->atomic,
> + (uint32_t __user *)(unsigned long)(out_resp->props_ptr),
> + (uint64_t __user *)(unsigned long)(out_resp->prop_values_ptr),
> + &out_resp->count_props);
> + drm_modeset_unlock(&dev->mode_config.connection_mutex);
> +
> +out:
> drm_connector_put(connector);
>
> return ret;
> --
> 2.11.0
--
Sean Paul, Software Engineer, Google / Chromium OS
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