diff options
| author | Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> | 2025-07-31 20:07:45 +0900 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-07-31 15:01:07 -0600 |
| commit | 765761851d89c772f482494d452e266795460278 (patch) | |
| tree | 30237b78e38a3c56733dd6e24e9786cb8e198817 | |
| parent | e2ba58ccc9099514380c3300cbc0750b5055fc1c (diff) | |
zloop: fix KASAN use-after-free of tag set
When a zoned loop device, or zloop device, is removed, KASAN enabled
kernel reports "BUG KASAN use-after-free" in blk_mq_free_tag_set(). The
BUG happens because zloop_ctl_remove() calls put_disk(), which invokes
zloop_free_disk(). The zloop_free_disk() frees the memory allocated for
the zlo pointer. However, after the memory is freed, zloop_ctl_remove()
calls blk_mq_free_tag_set(&zlo->tag_set), which accesses the freed zlo.
Hence the KASAN use-after-free.
zloop_ctl_remove()
put_disk(zlo->disk)
put_device()
kobject_put()
...
zloop_free_disk()
kvfree(zlo)
blk_mq_free_tag_set(&zlo->tag_set)
To avoid the BUG, move the call to blk_mq_free_tag_set(&zlo->tag_set)
from zloop_ctl_remove() into zloop_free_disk(). This ensures that
the tag_set is freed before the call to kvfree(zlo).
Fixes: eb0570c7df23 ("block: new zoned loop block device driver")
CC: stable@vger.kernel.org
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250731110745.165751-1-shinichiro.kawasaki@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | drivers/block/zloop.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/block/zloop.c b/drivers/block/zloop.c index 553b1a713ab9..a423228e201b 100644 --- a/drivers/block/zloop.c +++ b/drivers/block/zloop.c @@ -700,6 +700,8 @@ static void zloop_free_disk(struct gendisk *disk) struct zloop_device *zlo = disk->private_data; unsigned int i; + blk_mq_free_tag_set(&zlo->tag_set); + for (i = 0; i < zlo->nr_zones; i++) { struct zloop_zone *zone = &zlo->zones[i]; @@ -1080,7 +1082,6 @@ static int zloop_ctl_remove(struct zloop_options *opts) del_gendisk(zlo->disk); put_disk(zlo->disk); - blk_mq_free_tag_set(&zlo->tag_set); pr_info("Removed device %d\n", opts->id); |