Re: Memory hotplug softlock issue

From: Vlastimil Babka
Date: Mon Nov 19 2018 - 12:41:34 EST


On 11/19/18 5:46 PM, Michal Hocko wrote:
> On Mon 19-11-18 17:36:21, Vlastimil Babka wrote:
>>
>> So what protects us from locking a page whose refcount dropped to zero?
>> and is being freed? The checks in freeing path won't be happy about a
>> stray lock.
>
> Nothing really prevents that. But does it matter. The worst that might
> happen is that we lock a freed or reused page. Who would complain?

free_pages_check() for example

PAGE_FLAGS_CHECK_AT_FREE includes PG_locked