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| author | Doug Berger <opendmb@gmail.com> | 2022-09-14 22:09:17 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-10-05 11:40:47 +0300 |
| commit | fcc9261c2b5f7388325232c51c708effced4c430 (patch) | |
| tree | e705e3871599d033f76dc5d1093b95a0f0e287d2 | |
| parent | f9cedf6b357e33d9449a68f1aa9a70225146bf08 (diff) | |
| download | linux-fcc9261c2b5f7388325232c51c708effced4c430.tar.xz | |
mm/hugetlb: correct demote page offset logic
commit 317314527d173e1f139ceaf8cb87cb1746abf240 upstream.
With gigantic pages it may not be true that struct page structures are
contiguous across the entire gigantic page. The nth_page macro is used
here in place of direct pointer arithmetic to correct for this.
Mike said:
: This error could cause addressing exceptions. However, this is only
: possible in configurations where CONFIG_SPARSEMEM &&
: !CONFIG_SPARSEMEM_VMEMMAP. Such a configuration option is rare and
: unknown to be the default anywhere.
Link: https://lkml.kernel.org/r/20220914190917.3517663-1-opendmb@gmail.com
Fixes: 8531fc6f52f5 ("hugetlb: add hugetlb demote page support")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | mm/hugetlb.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 299dcfaa35b2..b508efbdcdbe 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3418,6 +3418,7 @@ static int demote_free_huge_page(struct hstate *h, struct page *page) { int i, nid = page_to_nid(page); struct hstate *target_hstate; + struct page *subpage; int rc = 0; target_hstate = size_to_hstate(PAGE_SIZE << h->demote_order); @@ -3451,15 +3452,16 @@ static int demote_free_huge_page(struct hstate *h, struct page *page) mutex_lock(&target_hstate->resize_lock); for (i = 0; i < pages_per_huge_page(h); i += pages_per_huge_page(target_hstate)) { + subpage = nth_page(page, i); if (hstate_is_gigantic(target_hstate)) - prep_compound_gigantic_page_for_demote(page + i, + prep_compound_gigantic_page_for_demote(subpage, target_hstate->order); else - prep_compound_page(page + i, target_hstate->order); - set_page_private(page + i, 0); - set_page_refcounted(page + i); - prep_new_huge_page(target_hstate, page + i, nid); - put_page(page + i); + prep_compound_page(subpage, target_hstate->order); + set_page_private(subpage, 0); + set_page_refcounted(subpage); + prep_new_huge_page(target_hstate, subpage, nid); + put_page(subpage); } mutex_unlock(&target_hstate->resize_lock); |