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authorMike Kravetz <mike.kravetz@oracle.com>2022-04-15 05:13:52 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2022-04-16 00:49:55 +0300
commit5a317412ef884763fdf7aa17f9f3636959d11d8f (patch)
tree28d3f08cd0e8a61139d2cf79fc67d2bc6d22851f
parent31ca72fa7540bb654b55c56adaf99305847376e0 (diff)
downloadlinux-5a317412ef884763fdf7aa17f9f3636959d11d8f.tar.xz
hugetlb: do not demote poisoned hugetlb pages
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: 8531fc6f52f5 ("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>
-rw-r--r--mm/hugetlb.c17
1 files changed, 10 insertions, 7 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index b34f50156f7e..f8ca7cca3c1a 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -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) \