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| author | Christophe JAILLET <christophe.jaillet@wanadoo.fr> | 2022-03-26 15:50:46 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-08 14:24:11 +0200 |
| commit | 5b9ac3727e4abb11c9cfbe9c0781fc05dfdd7cfb (patch) | |
| tree | 277d4b98be8b8852da32cd94f5beb7baa630bb67 | |
| parent | 21cfddd5e0f6ef438fbae84924669ca6d6701b27 (diff) | |
| download | linux-stable-5b9ac3727e4abb11c9cfbe9c0781fc05dfdd7cfb.tar.gz linux-stable-5b9ac3727e4abb11c9cfbe9c0781fc05dfdd7cfb.tar.bz2 linux-stable-5b9ac3727e4abb11c9cfbe9c0781fc05dfdd7cfb.zip | |
block: Fix the maximum minor value is blk_alloc_ext_minor()
commit d1868328dec5ae2cf210111025fcbc71f78dd5ca upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 0276a2846adf..74e19d67ceab 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -324,7 +324,7 @@ 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; |