Hi,

quoted

On Jan 12, 2023, at 4:30 AM, Wang Yugui [off-list ref] wrote:

Hi,

quoted

Hi,

quoted

Hi,

We noticed a dead lock of 'umount.nfs4 /nfs/scratch -l'

reproducer:

mount /dev/sda1 /mnt/test/
mount /dev/sda2 /mnt/scratch/
systemctl restart nfs-server.service
mount.nfs4 127.0.0.1:/mnt/test/ /nfs/test/
mount.nfs4 127.0.0.1:/mnt/scratch/ /nfs/scratch/
systemctl stop nfs-server.service
umount -l /nfs/scratch #OK
umount -l /nfs/test #dead lock

Best Regards
Wang Yugui (wangyugui@e16-tech.com)
2023/01/11

quoted

kernel: 6.1.5-rc1

This problem happen on kernel 6.2.0-rc3+(upstream) too.

Can you clarify:

- By "deadlock" do you mean the system becomes unresponsive, or that
  just the mount is stuck?

Just the 'mount -l' is stuck.
'Ctrl +C' can stop the 'mount -l', and then the mount point disapear.

- Can you reproduce in a non-loopback scenario: a separate client and
  server?

Yes. It happened on separate nfs client and  server too.

tested kernel version: 5.15.85, 6.1.5, 6.2.0-rc3+(upstream)

Best Regards
Wang Yugui (wangyugui@e16-tech.com)
2023/01/14