Commit a3163431 authored Nov 08, 2023 by Tetsuo Handa Committed by Li Nan Nov 07, 2023

block: check minor range in device_add_disk()

mainline inclusion
from mainline-v5.17-rc1
commit e338924b
category: bugfix
bugzilla: 188733

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e338924bd05d6e71574bc13e310c89e10e49a8a5



----------------------------------------

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


Signed-off-by: Jens Axboe <axboe@kernel.dk>
conflict:
  block/genhd.c
Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com>
Signed-off-by: Li Nan <linan122@huawei.com>

parent 99283414

block/genhd.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -795,6 +795,9 @@ static int __device_add_disk(struct device parent, struct gendisk disk,
		WARN_ON(!disk->minors &&
		!(disk->flags & (GENHD_FL_EXT_DEVT \| GENHD_FL_HIDDEN)));

		if (disk->minors != 0 &&
		disk->first_minor + disk->minors > MINORMASK + 1)
		goto out_exit_elevator;
		retval = blk_alloc_devt(&disk->part0, &devt);
		if (retval)
		goto out_exit_elevator;