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| author | Christophe JAILLET <christophe.jaillet@wanadoo.fr> | 2022-03-26 17:50:46 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-03-28 15:34:30 +0300 |
| commit | d1868328dec5ae2cf210111025fcbc71f78dd5ca (patch) | |
| tree | 8dbb62158a9b259e4f838401fcffeb08e6c707c9 /block/genhd.c | |
| parent | 15583a563cd5a7358e975599b7de7caacd9e9ce9 (diff) | |
| download | linux-d1868328dec5ae2cf210111025fcbc71f78dd5ca.tar.xz | |
block: Fix the maximum minor value is blk_alloc_ext_minor()
ida_alloc_range(..., min, max, ...) returns values from min to max,
inclusive.
So, NR_EXT_DEVT is a valid idx returned by blk_alloc_ext_minor().
This is an issue because in device_add_disk(), this value is used in:
ddev->devt = MKDEV(disk->major, disk->first_minor);
and NR_EXT_DEVT is '(1 << MINORBITS)'.
So, should 'disk->first_minor' be NR_EXT_DEVT, it would overflow.
Fixes: 22ae8ce8b892 ("block: simplify bdev/disk lookup in blkdev_get")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/cc17199798312406b90834e433d2cefe8266823d.1648306232.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/genhd.c')
| -rw-r--r-- | block/genhd.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/block/genhd.c b/block/genhd.c index 8244f09e058d..19b8a6e7a13b 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -335,7 +335,7 @@ int blk_alloc_ext_minor(void) { int idx; - idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT, GFP_KERNEL); + idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT - 1, GFP_KERNEL); if (idx == -ENOSPC) return -EBUSY; return idx; |