dm ioctl: fix nested locking in table_clear() to remove deadlock concern

mainline inclusion
from mainline-v6.4-rc1
commit 3d32aaa7
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I6YQZS
CVE: CVE-2023-2269

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=3d32aaa7e66d5c1479a3c31d6c2c5d45dd0d3b89

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

syzkaller found the following problematic rwsem locking (with write
lock already held):

 down_read+0x9d/0x450 kernel/locking/rwsem.c:1509
 dm_get_inactive_table+0x2b/0xc0 drivers/md/dm-ioctl.c:773
 __dev_status+0x4fd/0x7c0 drivers/md/dm-ioctl.c:844
 table_clear+0x197/0x280 drivers/md/dm-ioctl.c:1537

In table_clear, it first acquires a write lock
https://elixir.bootlin.com/linux/v6.2/source/drivers/md/dm-ioctl.c#L1520
down_write(&_hash_lock);

Then before the lock is released at L1539, there is a path shown above:
table_clear -> __dev_status -> dm_get_inactive_table ->  down_read
https://elixir.bootlin.com/linux/v6.2/source/drivers/md/dm-ioctl.c#L773
down_read(&_hash_lock);

It tries to acquire the same read lock again, resulting in the deadlock
problem.

Fix this by moving table_clear()'s __dev_status() call to after its
up_write(&_hash_lock);

Cc: stable@vger.kernel.org
Reported-by: NZheng Zhang <zheng.zhang@email.ucr.edu>
Signed-off-by: NMike Snitzer <snitzer@kernel.org>

Conflicts:
  drivers/md/dm-ioctl.c
Signed-off-by: NLi Lingfeng <lilingfeng3@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>

drivers/md/dm-ioctl.c

@@ -1446,11 +1446,12 @@ static int table_clear(struct file *filp, struct dm_ioctl *param, size_t param_s
 		hc->new_map = NULL;
 	}
 
-	param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
-
-	__dev_status(hc->md, param);
 	md = hc->md;
 	up_write(&_hash_lock);
+
+	param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
+	__dev_status(md, param);
+
 	if (old_map) {
 		dm_sync_table(md);
 		dm_table_destroy(old_map);