Commit f12bc113 authored Jun 05, 2023 by Zhong Jinghua Committed by Jens Axboe Jun 07, 2023

nbd: Add the maximum limit of allocated index in nbd_dev_add



If the index allocated by idr_alloc greater than MINORMASK >> part_shift,
the device number will overflow, resulting in failure to create a block
device.

Fix it by imiting the size of the max allocation.

Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230605122159.2134384-1-zhongjinghua@huaweicloud.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent ddf63516

drivers/block/nbd.c

+2 −1

Original line number	Original line	Diff line number	Diff line
	@@ -1776,7 +1776,8 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
	if (err == -ENOSPC)		if (err == -ENOSPC)
	err = -EEXIST;		err = -EEXIST;
	} else {		} else {
	err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);		err = idr_alloc(&nbd_index_idr, nbd, 0,
			(MINORMASK >> part_shift) + 1, GFP_KERNEL);
	if (err >= 0)		if (err >= 0)
	index = err;		index = err;
	}		}