Commit e338924b authored by Tetsuo Handa's avatar Tetsuo Handa Committed by Jens Axboe
Browse files

block: check minor range in device_add_disk() 



ioctl(fd, LOOP_CTL_ADD, 1048576) causes

  sysfs: cannot create duplicate filename '/dev/block/7:0'

message because such request is treated as if ioctl(fd, LOOP_CTL_ADD, 0)
due to MINORMASK == 1048575. Verify that all minor numbers for that device
fit in the minor range.

Reported-by: default avatarwangyangbo <wangyangbo@uniontech.com>
Signed-off-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/b1b19379-23ee-5379-0eb5-94bf5f79f1b4@i-love.sakura.ne.jp


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 37ae5a0f

block/genhd.c

+2 −0
Original line number Diff line number Diff line
@@ -431,6 +431,8 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk, 
				DISK_MAX_PARTS);

			disk->minors = DISK_MAX_PARTS;

		}

		if (disk->first_minor + disk->minors > MINORMASK + 1)

			return -EINVAL;

	} else {

		if (WARN_ON(disk->minors))

			return -EINVAL;