From 6434e69814b159608a23135ca2be36024f402717 Mon Sep 17 00:00:00 2001 From: Barry Song Date: Fri, 24 May 2024 12:54:44 +1200 Subject: [PATCH] mm: arm64: fix the out-of-bounds issue in contpte_clear_young_dirty_ptes We are passing a huge nr to __clear_young_dirty_ptes() right now. While we should pass the number of pages, we are actually passing CONT_PTE_SIZE. This is causing lots of crashes of MADV_FREE, panic oops could vary everytime. Link: https://lkml.kernel.org/r/20240524005444.135417-1-21cnbao@gmail.com Fixes: 89e86854fb0a ("mm/arm64: override clear_young_dirty_ptes() batch helper") Signed-off-by: Barry Song Reviewed-by: Baolin Wang Acked-by: Lance Yang Acked-by: David Hildenbrand Acked-by: Chris Li Cc: Barry Song <21cnbao@gmail.com> Cc: Ryan Roberts Cc: Jeff Xie Cc: Kefeng Wang Cc: Michal Hocko Cc: Minchan Kim Cc: Muchun Song Cc: Peter Xu Cc: Yang Shi Cc: Yin Fengwei Cc: Zach O'Keefe Cc: Catalin Marinas Cc: Will Deacon Signed-off-by: Andrew Morton --- arch/arm64/mm/contpte.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c index 9f9486de0004..a3edced29ac1 100644 --- a/arch/arm64/mm/contpte.c +++ b/arch/arm64/mm/contpte.c @@ -376,7 +376,7 @@ void contpte_clear_young_dirty_ptes(struct vm_area_struct *vma, * clearing access/dirty for the whole block. */ unsigned long start = addr; - unsigned long end = start + nr; + unsigned long end = start + nr * PAGE_SIZE; if (pte_cont(__ptep_get(ptep + nr - 1))) end = ALIGN(end, CONT_PTE_SIZE); @@ -386,7 +386,7 @@ void contpte_clear_young_dirty_ptes(struct vm_area_struct *vma, ptep = contpte_align_down(ptep); } - __clear_young_dirty_ptes(vma, start, ptep, end - start, flags); + __clear_young_dirty_ptes(vma, start, ptep, (end - start) / PAGE_SIZE, flags); } EXPORT_SYMBOL_GPL(contpte_clear_young_dirty_ptes);