Re: [PATCH] mm: hugetlb: fix dissolve_free_huge_page use of tail/head page
From: Michal Hocko <mhocko@suse.com>
Date: 2021-05-31 06:49:04
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On Thu 27-05-21 16:12:25, Mike Kravetz wrote:
The routine dissolve_free_huge_page can be passed the tail page of a hugetlb page. The tail page is incorrectly passed on to the routines alloc_huge_page_vmemmap and add_hugetlb_page which expect a hugetlb head page. Operating on a tail page instead of head page could result in addressing exceptions or vmemmap corruption. Signed-off-by: Mike Kravetz <redacted>
Acked-by: Michal Hocko <mhocko@suse.com>
--- The code with this issue is only in mmotm (and next). Specifically mm: hugetlb: alloc the vmemmap pages associated with each HugeTLB page Andrew, I assume you will fix in your tree.
Yes, folding this in sounds like the best way forward.
quoted hunk ↗ jump to hunk
mm/hugetlb.c | 4 ++-- scripts/rust-version.sh | 0 2 files changed, 2 insertions(+), 2 deletions(-) mode change 100644 => 100755 scripts/rust-version.shdiff --git a/mm/hugetlb.c b/mm/hugetlb.c index 69a4b551c157..d2461c1f32dd 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c@@ -1954,7 +1954,7 @@ int dissolve_free_huge_page(struct page *page) * Attempt to allocate vmemmmap here so that we can take * appropriate action on failure. */ - rc = alloc_huge_page_vmemmap(h, page); + rc = alloc_huge_page_vmemmap(h, head); if (!rc) { /* * Move PageHWPoison flag from head page to the raw@@ -1968,7 +1968,7 @@ int dissolve_free_huge_page(struct page *page) update_and_free_page(h, head, false); } else { spin_lock_irq(&hugetlb_lock); - add_hugetlb_page(h, page, false); + add_hugetlb_page(h, head, false); h->max_huge_pages++; spin_unlock_irq(&hugetlb_lock); }diff --git a/scripts/rust-version.sh b/scripts/rust-version.sh old mode 100644 new mode 100755 -- 2.31.1
-- Michal Hocko SUSE Labs