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Commit a48a62bc authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/sysfs: Grab lock for edid/modes_show 

We chase pointers/lists without taking the locks protecting them,
which isn't that good.

Fix it.

v2: Actually unlock properly, spotted by Julia.

v3: Put the label _before_ the mutex_unlock (Emil)

Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Link: http://patchwork.freedesktop.org/patch/msgid/1443783662-23066-1-git-send-email-daniel.vetter@ffwll.ch


Reviewed-by: default avatarEmil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent f980a71a

drivers/gpu/drm/drm_sysfs.c

+12 −4
Original line number Diff line number Diff line
@@ -256,23 +256,29 @@ 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;

unlock:

	mutex_unlock(&connector->dev->mode_config.mutex);



	return ret;

}



static ssize_t modes_show(struct device *device,
@@ -283,10 +289,12 @@ 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;

}