Description of problem:
5.10 arm（x86无问题）版本kernelSelftest测试集中vm子目录下的userfaultfd用例会hung住

Version-Release number of selected component (if applicable):
# uname -a
Linux l57h15219.sqa.nu8 5.10.84-146.git.6069f9229.an8.aarch64 #1 SMP Mon Jan 24 13:15:40 UTC 2022 aarch64 aarch64 aarch64 GNU/Linux
# cat /etc/os-release
NAME="Anolis OS"
VERSION="8.2"
ID="anolis"
ID_LIKE="rhel fedora centos"
VERSION_ID="8.2"
PLATFORM_ID="platform:an8"
PRETTY_NAME="Anolis OS 8.2"
ANSI_COLOR="0;31"
HOME_URL="https://openanolis.org/"


How reproducible:


Steps to Reproduce:
1.下载kernel源码包
2.cd tools/testing/selftests
3../userfaultfd anon 128 32

Actual results:
# ./userfaultfd anon 128 32
nr_pages: 32760, nr_pages_per_cpu: 936
bounces: 31, mode: rnd racing ver poll, userfaults: 674 missing (53+41+39+48+34+21+23+35+22+32+24+37+27+28+19+21+27+14+10+24+10+19+9+6+4+5+9+3+4+9+6+5+3+2+1), 0 wp (0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0+0)
bounces: 30, mode: racing ver poll,


Expected results:


Additional info:
 当用例hung住时，另起窗口执行strace跟踪进程，用例就会自动往下执行，否则会一直hung住不动
[问题发生概率]：必现