From: Yu Kuai <yukuai3@huawei.com> stable inclusion from stable-v5.10.170 commit 2e0c3e43ebb99c2b495229f8fade4c043fbd06a5 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I81XCK Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ---------------------------------------- commit 940c264984fd1457918393c49674f6b39ee16506 upstream. If 'part_shift' is not zero, then 'index << part_shift' might overflow to a value that is not greater than '0xfffff', then sysfs might complains about duplicate creation. Fixes: b0d9111a2d53 ("nbd: use an idr to keep track of nbd devices") Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Link: https://lore.kernel.org/r/20211102015237.2309763-3-yebin10@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Wen Yang <wenyang.linux@foxmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com> Signed-off-by: Li Nan <linan122@huawei.com> --- drivers/block/nbd.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index ce88c67be34b..fcb2a2ddca81 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1839,11 +1839,11 @@ static int nbd_dev_add(int index) disk->major = NBD_MAJOR; /* Too big first_minor can cause duplicate creation of - * sysfs files/links, since MKDEV() expect that the max bits of - * first_minor is 20. + * sysfs files/links, since index << part_shift might overflow, or + * MKDEV() expect that the max bits of first_minor is 20. */ disk->first_minor = index << part_shift; - if (disk->first_minor > MINORMASK) { + if (disk->first_minor < index || disk->first_minor > MINORMASK) { err = -EINVAL; goto out_free_idr; } -- 2.39.2