From: Zi Yan ziy@nvidia.com
stable inclusion from stable-v6.6.3 commit 18576d128e9bc91aa1eac85e2f93909ebc24ee2a category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8LBQP
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 426056efe835cf4864ccf4c328fe3af9146fc539 upstream.
When dealing with hugetlb pages, manipulating struct page pointers directly can get to wrong struct page, since struct page is not guaranteed to be contiguous on SPARSEMEM without VMEMMAP. Use nth_page() to handle it properly.
A wrong or non-existing page might be tried to be grabbed, either leading to a non freeable page or kernel memory access errors. No bug is reported. It comes from code inspection.
Link: https://lkml.kernel.org/r/20230913201248.452081-3-zi.yan@sent.com Fixes: 57a196a58421 ("hugetlb: simplify hugetlb handling in follow_page_mask") Signed-off-by: Zi Yan ziy@nvidia.com Reviewed-by: Muchun Song songmuchun@bytedance.com Cc: David Hildenbrand david@redhat.com Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: Mike Kravetz mike.kravetz@oracle.com Cc: Mike Rapoport (IBM) rppt@kernel.org Cc: Thomas Bogendoerfer tsbogend@alpha.franken.de Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- mm/hugetlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 50c3bfcef60c..1a4d388b6a3b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -6570,7 +6570,7 @@ struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma, } }
- page += ((address & ~huge_page_mask(h)) >> PAGE_SHIFT); + page = nth_page(page, ((address & ~huge_page_mask(h)) >> PAGE_SHIFT));
/* * Note that page may be a sub-page, and with vmemmap