From 7a5b09555114847add362fcd0174b00806580378 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Thu, 8 Dec 2022 11:15:21 +0000 Subject: [PATCH] mm,hugetlb: take hugetlb_lock before decrementing h->resv_huge_pages stable inclusion from stable-v4.19.264 commit 2b35432d324898ec41beb27031d2a1a864a4d40e category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I63UEU CVE: NA -------------------------------- commit 12df140f0bdfae5dcfc81800970dd7f6f632e00c upstream. The h->*_huge_pages counters are protected by the hugetlb_lock, but alloc_huge_page has a corner case where it can decrement the counter outside of the lock. This could lead to a corrupted value of h->resv_huge_pages, which we have observed on our systems. Take the hugetlb_lock before decrementing h->resv_huge_pages to avoid a potential race. Link: https://lkml.kernel.org/r/20221017202505.0e6a4fcd@imladris.surriel.com Fixes: a88c76954804 ("mm: hugetlb: fix hugepage memory leak caused by wrong reserve count") Signed-off-by: Rik van Riel Reviewed-by: Mike Kravetz Cc: Naoya Horiguchi Cc: Glen McCready Cc: Mike Kravetz Cc: Muchun Song Cc: Signed-off-by: Andrew Morton Signed-off-by: Mike Kravetz Signed-off-by: Greg Kroah-Hartman Signed-off-by: Yongqiang Liu --- mm/hugetlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index e8ef6c62da34..fb1f90eed7fc 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2271,11 +2271,11 @@ struct page *alloc_huge_page(struct vm_area_struct *vma, page = alloc_buddy_huge_page_with_mpol(h, vma, addr); if (!page) goto out_uncharge_cgroup; + spin_lock(&hugetlb_lock); if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) { SetPagePrivate(page); h->resv_huge_pages--; } - spin_lock(&hugetlb_lock); list_move(&page->lru, &h->hugepage_activelist); /* Fall through */ } -- GitLab