Re: [PATCH v2 6/6] mm: hugetlb: remove VM_BUG_ON_PAGE from page_huge_active
From: Michal Hocko <mhocko@suse.com>
Date: 2021-01-06 17:17:22
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On Wed 06-01-21 16:47:39, Muchun Song wrote:
The page_huge_active() can be called from scan_movable_pages() which
do not hold a reference count to the HugeTLB page. So when we call
page_huge_active() from scan_movable_pages(), the HugeTLB page can
be freed parallel. Then we will trigger a BUG_ON which is in the
page_huge_active() when CONFIG_DEBUG_VM is enabled. Just remove the
VM_BUG_ON_PAGE.
Fixes: 7e1f049efb86 ("mm: hugetlb: cleanup using paeg_huge_active()")
Signed-off-by: Muchun Song <redacted>
Reviewed-by: Mike Kravetz <redacted>Acked-by: Michal Hocko <mhocko@suse.com> The BUG_ON looks like a wrong thing to do regardless of the memory hotplug use. Which is admittedly ugly as well.
quoted hunk ↗ jump to hunk
--- mm/hugetlb.c | 1 - 1 file changed, 1 deletion(-)diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 67200dd25b1d..7a24ed28ec4f 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c@@ -1372,7 +1372,6 @@ struct hstate *size_to_hstate(unsigned long size) */ bool page_huge_active(struct page *page) { - VM_BUG_ON_PAGE(!PageHuge(page), page); return PageHead(page) && PagePrivate(&page[1]); }-- 2.11.0
-- Michal Hocko SUSE Labs