Re: [PATCH v3 3/6] mm: hugetlb: fix a race between freeing and dissolving the page
From: Michal Hocko <mhocko@suse.com>
Date: 2021-01-12 10:03:17
Also in:
lkml, stable
On Sun 10-01-21 20:40:14, Muchun Song wrote: [...]
quoted hunk ↗ jump to hunk
@@ -1770,6 +1788,14 @@ int dissolve_free_huge_page(struct page *page) int nid = page_to_nid(head); if (h->free_huge_pages - h->resv_huge_pages == 0) goto out; + + /* + * We should make sure that the page is already on the free list + * when it is dissolved. + */ + if (unlikely(!PageHugeFreed(head))) + goto out; +
Do you really want to report EBUSY in this case? This doesn't make much sense to me TBH. I believe you want to return 0 same as when you race and the page is no longer PageHuge.
/* * Move PageHWPoison flag from head page to the raw error page, * which makes any subpages rather than the error page reusable. -- 2.11.0
-- Michal Hocko SUSE Labs