On 11/19/18 5:46 PM, Vlastimil Babka wrote: > 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 And besides... what about the last page being offlined and then the whole struct page's part of vmemmap destroyed as the node goes away?
