From: Zhong Jinghua <zhongjinghua@xxxxxxxxxx> [ Upstream commit f12bc113ce904777fd6ca003b473b427782b3dde ] 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@xxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Link: https://lore.kernel.org/r/20230605122159.2134384-1-zhongjinghua@xxxxxxxxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/block/nbd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index dd0adcf745ff5..f0cdc5c576d9d 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1776,7 +1776,8 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs) if (err == -ENOSPC) err = -EEXIST; } 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) index = err; } -- 2.39.2
