From: Guo Hui guohui@uniontech.com

uniontech inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I3RFV8 CVE: NA

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Commit eb761d6521c3 ("mm: parallelize deferred struct page initialization within each node") the code "++zone" in follow code: /* Sanity check that the next zone really is unpopulated */ WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone)); VM_BUG_ON(nr_init != nr_free);

zone->managed_pages += nr_free;

makes the managed_pages statistics of the current zone incorrect and the zone may have out-of-bounds memory when CONFIG_DEFERRED_STRUCT_PAGE_INIT=y, causing the Virtual machine system startup to fail when the Virtual machine system current allocated memory is set to half of the Virtual machine maximum memory using virt-manager tool

Fix it by putting the code “zone->managed_pages += nr_free;” before “++zone” code

Fixes: eb761d6521c3 ("mm: parallelize deferred struct page initialization within each node") Reported-by: Peng Yuanbo pengyuanbo@uniontech.com Signed-off-by: Guo Hui guohui@uniontech.com Reviewed-by: Kefeng Wang wangkefeng.wang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- mm/page_alloc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c index cdd8ff4350ba7..d2012e07e5295 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1688,12 +1688,13 @@ static int __init deferred_init_memmap(void *data) nr_free += atomic64_read(&args.nr_pages); }

- /* Sanity check that the next zone really is unpopulated */ - WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone)); VM_BUG_ON(nr_init != nr_free);

zone->managed_pages += nr_free;

+ /* Sanity check that the next zone really is unpopulated */ + WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone)); + pr_info("node %d initialised, %lu pages in %ums\n", nid, nr_free, jiffies_to_msecs(jiffies - start));