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hugetlb: do not demote poisoned hugetlb pages

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It is possible for poisoned hugetlb pages to reside on the free lists.
The huge page allocation routines which dequeue entries from the free
lists make a point of avoiding poisoned pages.  There is no such check
and avoidance in the demote code path.

If a hugetlb page on the is on a free list, poison will only be set in
the head page rather then the page with the actual error.  If such a
page is demoted, then the poison flag may follow the wrong page.  A page
without error could have poison set, and a page with poison could not
have the flag set.

Check for poison before attempting to demote a hugetlb page.  Also,
return -EBUSY to the caller if only poisoned pages are on the free list.

Link: https://lkml.kernel.org/r/20220307215707.50916-1-mike.kravetz@oracle.com
Fixes: 8531fc6f52 ("hugetlb: add hugetlb demote page support")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mike Kravetz 2022-04-14 19:13:52 -07:00 committed by Linus Torvalds
parent 31ca72fa75
commit 5a317412ef
1 changed files with 10 additions and 7 deletions
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17
mm/hugetlb.c
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@ -3475,7 +3475,6 @@ static int demote_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
{
int nr_nodes, node;
struct page *page;
int rc = 0;
lockdep_assert_held(&hugetlb_lock);
@ -3486,15 +3485,19 @@ static int demote_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
}
for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
if (!list_empty(&h->hugepage_freelists[node])) {
page = list_entry(h->hugepage_freelists[node].next,
struct page, lru);
rc = demote_free_huge_page(h, page);
break;
list_for_each_entry(page, &h->hugepage_freelists[node], lru) {
if (PageHWPoison(page))
continue;
return demote_free_huge_page(h, page);
}
}
return rc;
/*
* Only way to get here is if all pages on free lists are poisoned.
* Return -EBUSY so that caller will not retry.
*/
return -EBUSY;
}
#define HSTATE_ATTR_RO(_name) \