rbd: get/put img_request in rbd_img_request_submit() (663ae2cc) · Commits · 戴 / test

By the time we get to checking for_each_obj_request_safe(img_request) terminating condition, all obj_requests may be complete and img_request ref, that rbd_img_request_submit() takes away from its caller, may be put. Moving the next_obj_request cursor is then a use-after-free on img_request. It's totally benign, as the value that's read is never used, but I think it's still worth fixing. Cc: Alex Elder <elder@linaro.org> Signed-off-by:

Ilya Dryomov <idryomov@gmail.com>

drivers/block/rbd.c

+7 −4

Original line number	Diff line number	Diff line
		@@ -2973,17 +2973,20 @@ static int rbd_img_request_submit(struct rbd_img_request *img_request)
		{
		struct rbd_obj_request *obj_request;
		struct rbd_obj_request *next_obj_request;
		int ret = 0;

		dout("%s: img %p\n", __func__, img_request);
		for_each_obj_request_safe(img_request, obj_request, next_obj_request) {
		int ret;

		rbd_img_request_get(img_request);
		for_each_obj_request_safe(img_request, obj_request, next_obj_request) {
		ret = rbd_img_obj_request_submit(obj_request);
		if (ret)
		return ret;
		goto out_put_ireq;
		}

		return 0;
		out_put_ireq:
		rbd_img_request_put(img_request);
		return ret;
		}

		static void rbd_img_parent_read_callback(struct rbd_img_request *img_request)

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