Re: WARNING: lock held when returning to user space in grab_super

[Tejun Heo]

Happy new year, Tetsuo.

On Wed, Jan 02, 2019 at 09:08:56PM +0900, Tetsuo Handa wrote:
> According to commit 633feee310de6b6c ("cgroup: refactor mount path and
> clearly distinguish v1 and v2 paths"), cgroup_do_mount() is failing to
> do full teardown steps for kernfs_mount() (deactivate_locked_super() ?)
> when kernfs_node_dentry() failed.

Hmm... that's basically dget()'ing the root dentry of the sb.  I'm not
sure how that could fail.  Can it?

Thanks.

-- 
tejun