| Message ID | 20210117204436.awIpnPC-N%akpm@linux-foundation.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [to-be-updated] mm-hugetlb-fix-a-race-between-isolating-and-freeing-page.patch removed from -mm tree | expand |
--- a/mm/hugetlb.c~mm-hugetlb-fix-a-race-between-isolating-and-freeing-page +++ a/mm/hugetlb.c @@ -5581,9 +5581,9 @@ bool isolate_huge_page(struct page *page { bool ret = true; - VM_BUG_ON_PAGE(!PageHead(page), page); spin_lock(&hugetlb_lock); - if (!page_huge_active(page) || !get_page_unless_zero(page)) { + if (!PageHeadHuge(page) || !page_huge_active(page) || + !get_page_unless_zero(page)) { ret = false; goto unlock; }
The patch titled Subject: mm: hugetlb: fix a race between isolating and freeing page has been removed from the -mm tree. Its filename was mm-hugetlb-fix-a-race-between-isolating-and-freeing-page.patch This patch was dropped because an updated version will be merged ------------------------------------------------------ From: Muchun Song <songmuchun@bytedance.com> Subject: mm: hugetlb: fix a race between isolating and freeing page There is a race between isolate_huge_page() and __free_huge_page(). CPU0: CPU1: if (PageHuge(page)) put_page(page) __free_huge_page(page) spin_lock(&hugetlb_lock) update_and_free_page(page) set_compound_page_dtor(page, NULL_COMPOUND_DTOR) spin_unlock(&hugetlb_lock) isolate_huge_page(page) // trigger BUG_ON VM_BUG_ON_PAGE(!PageHead(page), page) spin_lock(&hugetlb_lock) page_huge_active(page) // trigger BUG_ON VM_BUG_ON_PAGE(!PageHuge(page), page) spin_unlock(&hugetlb_lock) When we isolate a HugeTLB page on CPU0. Meanwhile, we free it to the buddy allocator on CPU1. Then, we can trigger a BUG_ON on CPU0. Because it is already freed to the buddy allocator. Link: https://lkml.kernel.org/r/20210110124017.86750-6-songmuchun@bytedance.com Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- mm/hugetlb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)