dm: fix null pointer dereference in dev_create()

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I62762


CVE: NA

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

A crash as follows:
 BUG: KASAN: null-ptr-deref in dev_create.cold+0x12/0x77
 Read of size 8 at addr 0000000000000020 by task dmsetup/683

 CPU: 4 PID: 683 Comm: dmsetup Not tainted 5.10.0-01524-g884de6e91114-dirty #11
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
 Call Trace:
  ? dump_stack+0xdd/0x126
  ? kasan_report.cold+0xd1/0xdb
  ? dev_create.cold+0x12/0x77
  ? __asan_load8+0xae/0x110
  ? dev_create.cold+0x12/0x77
  ? dev_rename+0x720/0x720
  ? cap_capable+0xcf/0x130
  ? ctl_ioctl+0x2f5/0x750
  ? dev_rename+0x720/0x720
  ? free_params+0x50/0x50
  ? unmerge_queues+0x176/0x1b0
  ? __blkcg_punt_bio_submit+0x110/0x110
  ? mem_cgroup_handle_over_high+0x33/0x5e0
  ? dm_ctl_ioctl+0x12/0x20
  ? __se_sys_ioctl+0xc5/0x120
  ? __x64_sys_ioctl+0x46/0x60
  ? do_syscall_64+0x45/0x70
  ? entry_SYSCALL_64_after_hwframe+0x61/0xc6

This can be easily reproduced using:
  dmsetup create xxx --table "0 1000 linear /dev/sda 0"
  dmsetup remove xxx

Fix this by adding hass_lock in dev_create().

Fixes: a5100d07 ("dm ioctl: add DMINFO() to track dm device create/remove")

Signed-off-by: Luo Meng <luomeng12@huawei.com>
Reviewed-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>