ltp fs_bind_rbind28 failed

[sanwan]

What happened:

fs_bind_rbind28 1 TFAIL: umount parent1 failed unexpectedly
fs_bind_rbind28 1 TPASS: umount share1 passed as expected
fs_bind_rbind28 1 TFAIL: There are still mounts in the sandbox:
parent1
parent2
share1
parent1/child1
parent1/child1
parent1/child1
parent2
parent2/child1
parent2/child1
parent2/child1
fs_bind_rbind28 2 TINFO: AppArmor enabled, this may affect test results
fs_bind_rbind28 2 TINFO: it can be disabled with TST_DISABLE_APPARMOR=1 (requires super/root)
fs_bind_rbind28 2 TINFO: loaded AppArmor profiles: none

Summary:
passed 24
failed 7
broken 0
skipped 0
warnings 0
What you expected to happen:
The case passed .
How to reproduce it (as minimally and precisely as possible):
Follow the action https://github.com/juicedata/juicefs/runs/7925591856?check_suite_focus=true .
Anything else we need to know?
No .