Re: [PATCH] mm: arm64: Fix the out-of-bounds issue in contpte_clear_young_dirty_ptes
From: Baolin Wang
Date: Thu May 23 2024 - 23:41:09 EST
On 2024/5/24 08:54, Barry Song wrote:
From: Barry Song <v-songbaohua@xxxxxxxx>
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.
Fixes: 89e86854fb0a ("mm/arm64: override clear_young_dirty_ptes() batch helper")
Cc: Lance Yang <ioworker0@xxxxxxxxx>
Cc: Barry Song <21cnbao@xxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Jeff Xie <xiehuan09@xxxxxxxxx>
Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Yin Fengwei <fengwei.yin@xxxxxxxxx>
Cc: Zach O'Keefe <zokeefe@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
Good catch. Feel free to add:
Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
---
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);