Re: [PATCH 1/2] zram: fix crashes due to use of cpu hotplug multistate

[Luis Chamberlain]

On Tue, Apr 06, 2021 at 06:38:24PM -0700, Minchan Kim wrote:
> To clarify what I understood form the discussion until now:
> 
> 1. zram shouldn't allow creating more zram instance during
> rmmod(It causes CPU multistate splat)

Right!

> 2. the private data of gendisk shouldn't destroyed while zram
> sysfs knob is working(it makes system goes crash)

Yup, this is resolved with the bdgrab / bdput on each sysfs knob.

And the last issue is:

3) which patch 2/2 addresed. If a mutex is shared on sysfs
knobs and module removal, you must do try_module_get() to prevent
the deadlock.

  Luis