From aa5fe31b6b59210cb4ea28a59e68781f48eeca74 Mon Sep 17 00:00:00 2001 From: Zi Yan Date: Wed, 13 Sep 2023 16:12:48 -0400 Subject: [PATCH] mips: use nth_page() in place of direct struct page manipulation __flush_dcache_pages() is called during hugetlb migration via migrate_pages() -> migrate_hugetlbs() -> unmap_and_move_huge_page() -> move_to_new_folio() -> flush_dcache_folio(). And with hugetlb and without sparsemem vmemmap, struct page is not guaranteed to be contiguous beyond a section. Use nth_page() instead. Without the fix, a wrong address might be used for data cache page flush. No bug is reported. The fix comes from code inspection. Link: https://lkml.kernel.org/r/20230913201248.452081-6-zi.yan@sent.com Fixes: 15fa3e8e3269 ("mips: implement the new page table range API") Signed-off-by: Zi Yan Cc: David Hildenbrand Cc: Matthew Wilcox (Oracle) Cc: Mike Kravetz Cc: Mike Rapoport (IBM) Cc: Muchun Song Cc: Thomas Bogendoerfer Cc: Signed-off-by: Andrew Morton --- arch/mips/mm/cache.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c index 02042100e267..7f830634dbe7 100644 --- a/arch/mips/mm/cache.c +++ b/arch/mips/mm/cache.c @@ -117,7 +117,7 @@ void __flush_dcache_pages(struct page *page, unsigned int nr) * get faulted into the tlb (and thus flushed) anyways. */ for (i = 0; i < nr; i++) { - addr = (unsigned long)kmap_local_page(page + i); + addr = (unsigned long)kmap_local_page(nth_page(page, i)); flush_data_cache_page(addr); kunmap_local((void *)addr); } -- 2.39.5