On Fri, 2 Oct 2015, Daniel Vetter wrote:
> We chase pointers/lists without taking the locks protecting them,
> which isn't that good.
>
> Fix it.
>
> v2: Actually unlock properly, spotted by Julia.
The unlock is still on top of the unlock label?
julia
>
> Cc: Julia Lawall <julia.lawall at lip6.fr>
> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
> drivers/gpu/drm/drm_sysfs.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
> index 7506de0a75b4..9bffa63fe849 100644
> --- a/drivers/gpu/drm/drm_sysfs.c
> +++ b/drivers/gpu/drm/drm_sysfs.c
> @@ -261,23 +261,29 @@ static ssize_t edid_show(struct file *filp, struct
> kobject *kobj,
> struct drm_connector *connector = to_drm_connector(connector_dev);
> unsigned char *edid;
> size_t size;
> + ssize_t ret = 0;
>
> + mutex_lock(&connector->dev->mode_config.mutex);
> if (!connector->edid_blob_ptr)
> - return 0;
> + goto unlock;
>
> edid = connector->edid_blob_ptr->data;
> size = connector->edid_blob_ptr->length;
> if (!edid)
> - return 0;
> + goto unlock;
>
> if (off >= size)
> - return 0;
> + goto unlock;
>
> if (off + count > size)
> count = size - off;
> memcpy(buf, edid + off, count);
>
> - return count;
> + ret = count;
> + mutex_unlock(&connector->dev->mode_config.mutex);
> +unlock:
> +
> + return ret;
> }
>
> static ssize_t modes_show(struct device *device,
> @@ -288,10 +294,12 @@ static ssize_t modes_show(struct device *device,
> struct drm_display_mode *mode;
> int written = 0;
>
> + mutex_lock(&connector->dev->mode_config.mutex);
> list_for_each_entry(mode, &connector->modes, head) {
> written += snprintf(buf + written, PAGE_SIZE - written, "%s\n",
> mode->name);
> }
> + mutex_unlock(&connector->dev->mode_config.mutex);
>
> return written;
> }
> --
> 2.5.1
>
>
