From 5f09e534dfbb470dfe24c05a034ebcb71c9ad80a Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Wed, 22 Feb 2023 18:20:25 +0800 Subject: [PATCH] mm,hugetlb: take hugetlb_lock before decrementing h->resv_huge_pages mainline inclusion from mainline-v6.1-rc2 commit 12df140f0bdfae5dcfc81800970dd7f6f632e00c category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6EVPO Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=12df140f0bdfae5dcfc81800970dd7f6f632e00c -------------------------------- 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: Zhang Peng Reviewed-by: tong tiangen Reviewed-by: Kefeng Wang Signed-off-by: Jialin Zhang --- mm/hugetlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 9bfb781fafd3..03eca3aec0f6 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2641,11 +2641,11 @@ 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_irq(&hugetlb_lock); if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) { SetHPageRestoreReserve(page); h->resv_huge_pages--; } - spin_lock_irq(&hugetlb_lock); list_add(&page->lru, &h->hugepage_activelist); /* Fall through */ } -- GitLab