Re: drm_vm.c:drm_mmap: possible circular locking dependency detected

[Eric W. Biederman]

ebiederm@xxxxxxxxxxxx (Eric W. Biederman) writes:

> What to do about it is another question.   It has just recently come to my
> attention that we have more events like this

In the specific case of serio what gets us in trouble is
the call to sysfs_remove_group.

If instead of independent calls to sysfs_create_group/sysfs_remove_group,
you could move the groups into a list on dev->groups than we could solve
two problems.

- Userspace would see all of the attributes when the hotplug event is
  fired remove races.

- We would not hold serio->drv_mutex over sysfs_remove_group so there
  would not be a possible deadlock on device removal.

Does that change sound possible?

Eric


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