The patch titled
Subject: mm: hugetlb: fix dissolve_free_huge_page use of tail/head page
has been added to the -mm tree. Its filename is
mm-hugetlb-alloc-the-vmemmap-pages-associated-with-each-hugetlb-page-fix.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-alloc-the-vmemmap-pages-associated-with-each-hugetlb-page-fix.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-alloc-the-vmemmap-pages-associated-with-each-hugetlb-page-fix.patch
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------------------------------------------------------
From: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Subject: mm: hugetlb: fix dissolve_free_huge_page use of tail/head page
The routine dissolve_free_huge_page can be passed the tail page of a
hugetlb page. The tail page is incorrectly passed on to the routines
alloc_huge_page_vmemmap and add_hugetlb_page which expect a hugetlb head
page.
Operating on a tail page instead of head page could result in addressing
exceptions or vmemmap corruption.
Link: https://lkml.kernel.org/r/20210527231225.226987-1-mike.kravetz@xxxxxxxxxx
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/hugetlb.c~mm-hugetlb-alloc-the-vmemmap-pages-associated-with-each-hugetlb-page-fix
+++ a/mm/hugetlb.c
@@ -1954,7 +1954,7 @@ retry:
* Attempt to allocate vmemmmap here so that we can take
* appropriate action on failure.
*/
- rc = alloc_huge_page_vmemmap(h, page);
+ rc = alloc_huge_page_vmemmap(h, head);
if (!rc) {
/*
* Move PageHWPoison flag from head page to the raw
@@ -1968,7 +1968,7 @@ retry:
update_and_free_page(h, head, false);
} else {
spin_lock_irq(&hugetlb_lock);
- add_hugetlb_page(h, page, false);
+ add_hugetlb_page(h, head, false);
h->max_huge_pages++;
spin_unlock_irq(&hugetlb_lock);
}
_
Patches currently in -mm which might be from mike.kravetz@xxxxxxxxxx are
mm-hugetlb-alloc-the-vmemmap-pages-associated-with-each-hugetlb-page-fix.patch
